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BFM

BFM functionality is implemented in uart_bfm_pkg.vhd

Configuration Record

t_uart_bfm_config

Default value for the record is C_UART_BFM_CONFIG_DEFAULT.

Record element	Type	Default	Description
bit_time	time	-1 ns	The time it takes to transfer one bit. Will raise an error if not set.
num_data_bits	natural range 7 to 8	8	Number of data bits to send per transmission
idle_state	std_logic	‘1’	Bit value when line is idle
num_stop_bits	t_stop_bits	STOP_BITS_ONE	Number of stop-bits to use per transmission
parity	t_parity	PARITY_ODD	Transmission parity bit
timeout	time	0 ns	The maximum time to wait for the UART start bit on the RX line before timeout
timeout_severity	t_alert_level	ERROR	The above timeout will have this severity
num_bytes_to_log_before_expected_data	natural	10	Maximum number of bytes to save ahead of the expected data in the receive buffer. The bytes in the receive buffer will be logged.
match_strictness	t_match_strictness	MATCH_EXACT	Matching strictness for std_logic values in check procedures. MATCH_EXACT requires both values to be the same. Note that the expected value can contain the don’t care operator ‘-‘. MATCH_STD allows comparisons between ‘H’ and ‘1’, ‘L’ and ‘0’ and ‘-’ in both values.
id_for_bfm	t_msg_id	ID_BFM	Message ID used for logging general messages in the BFM
id_for_bfm_wait	t_msg_id	ID_BFM_WAIT	Message ID used for logging waits in the BFM
id_for_bfm_poll	t_msg_id	ID_BFM_POLL	DEPRECATED
id_for_bfm_poll_summary	t_msg_id	ID_BFM_POLL_SUMMARY	Message ID used for logging polling summary in the BFM
error_injection	t_bfm_error_injection	C_BFM_ERROR_INJECTION_INACTIVE	Record to set up error injection in the BFM procedure calls

t_bfm_error_injection

Default value for the record is C_BFM_ERROR_INJECTION_INACTIVE.

Record element	Type	Default	Description
parity_bit_error	boolean	false	Will invert the parity bit in a transmission if TRUE, and thus generate a parity error.
stop_bit_error	boolean	false	Will invert the first stop bit in a transmission if TRUE. Note that the following UART frame may be misinterpreted if there is no Idle period or additional stop bits after the error injection. Hence a stop_bit_error may lead to multiple following UART frame errors.

For more information on error injection, please see Protocol Aware Error Injection.

Methods

All signals are active high.
All parameters in brackets are optional.

Note

The BFM configuration has to be defined and used when calling the UART BFM procedures. See Local BFM configuration for an example of how to define a local BFM config.

uart_transmit()

Transmits data to the DUT using the UART protocol. For protocol details, see the UART specification.

The start bit, stop bit, parity, number of stop bits and number of data bits per transmission is defined in the ‘config’ parameter.

Errors may be injected depending on the ‘config.error_injection’ sub-record.

uart_transmit(data_value, msg, tx, [config, [scope, [msg_id_panel]]])

Object	Name	Dir.	Type	Description
constant	data_value	in	std_logic_vector	The data value to be transmitted to the DUT
constant	msg	in	string	A custom message to be appended in the log/alert
signal	tx	inout	std_logic	The UART BFM transmission signal. Must be connected to the UART DUT ‘rx’ port.
constant	config	in	t_uart_bfm_config	Configuration of BFM behavior and restrictions. Default value is C_UART_BFM_CONFIG_DEFAULT.
constant	scope	in	string	Describes the scope from which the log/alert originates. Default value is C_BFM_SCOPE (“UART BFM”).
constant	msg_id_panel	in	t_msg_id_panel	Controls verbosity within a specified scope. Default value is shared_msg_id_panel.

-- Examples:
uart_transmit(x"AA", "Transmitting data to DUT UART", tx);
uart_transmit(x"AA", "Transmitting data to DUT UART", tx, C_UART_BFM_CONFIG_DEFAULT, C_SCOPE, shared_msg_id_panel);

-- Suggested usage (requires local overload, see 'Local BFM overloads' section):
uart_transmit(C_ASCII_A, "Transmitting ASCII A to DUT UART");

uart_receive()

Receives data from the DUT using the UART protocol. For protocol details, see the UART specification.

When called, the procedure will wait for the start bit to be present on the rx line. The initial wait for the start bit will be terminated if one of the following occurs:

The start bit is present on the rx line.

The terminate_loop flag is set to ‘1’.

The number of clock cycles waited for the start bit exceeds ‘config.max_wait_cycles’ clock cycles.

Once all the bits have been received according to the UART specification, the parity and stop bit are checked. If correct, the read data is placed on the output ‘data_value’ and the procedure returns.

The procedure reports an alert if:

Timeout occurs, i.e. start bit does not occur within ‘config.max_wait_cycles’ clock cycles (alert level: ‘config.max_wait_cycles_severity’)

terminate_loop is set to ‘1’ (alert level: WARNING)

Expected stop_bit does not match received stop bit(s) (alert level: ERROR)

Calculated parity ‘config.parity’ does not match received parity (alert level: ERROR)

uart_receive(data_value, msg, rx, terminate_loop, [config, [scope, [msg_id_panel]]])

Object	Name	Dir.	Type	Description
variable	data_value	out	std_logic_vector	The data value received from the DUT
constant	msg	in	string	A custom message to be appended in the log/alert
signal	rx	in	std_logic	The UART BFM reception signal. Must be connected to the UART DUT ‘tx’ port.
signal	terminate_loop	in	std_logic	External control of loop termination to e.g. stop expect procedure prematurely
constant	config	in	t_uart_bfm_config	Configuration of BFM behavior and restrictions. Default value is C_UART_BFM_CONFIG_DEFAULT.
constant	scope	in	string	Describes the scope from which the log/alert originates. Default value is C_BFM_SCOPE (“UART BFM”).
constant	msg_id_panel	in	t_msg_id_panel	Controls verbosity within a specified scope. Default value is shared_msg_id_panel.

-- Examples:
uart_receive(v_data_out, "Receive from DUT UART", rx, terminate_signal);
uart_receive(v_data_out, "Receive from DUT UART", rx, terminate_signal, C_UART_BFM_CONFIG_DEFAULT, C_SCOPE, shared_msg_id_panel);

-- Suggested usage (requires local overload, see 'Local BFM overloads' section):
uart_receive(v_data_out, "Receive from DUT UART");

uart_expect()

Receives data from the DUT using the UART protocol described under uart_receive(). After receiving data from the DUT, the received data is compared with the expected data. If the received data does not match the expected data, another uart_receive() procedure will be initiated. This process will repeat until one of the following occurs:

The received data matches the expected data.

A timeout occurs.

The process has repeated ‘max_receptions’ number of times.

The ‘terminate_loop’ signal is set to ‘1’.

A log message with ID ‘config.id_for_bfm’ is issued when the procedure starts.
If the data was received successfully, and the received data matches the expected data, a log message is written with ID ‘config.id_for_bfm’.
If the received data did not match the expected data, an alert with severity ‘alert_level’ will be reported.
This procedure reports an alert if:

‘max_receptions’ and ‘timeout’ are set to 0, which will result in a possible infinite loop (alert_level: ERROR)

The expected data is not received within the time set in ‘timeout’ (alert_level: ‘alert_level’)

The expected data is not received within the number of received packets set in ‘max_receptions’ (alert_level: ‘alert_level’)

‘terminate_loop’ is set to ‘1’ (alert_level: WARNING)

The same alert conditions as the uart_receive() procedure.

uart_expect(data_exp, msg, rx, terminate_loop, [max_receptions, [timeout, [alert_level, [config, [scope, [msg_id_panel]]]]])

Object	Name	Dir.	Type	Description
constant	data_exp	in	std_logic_vector	The data value to expect when receiving the data. A mismatch results in an alert with severity ‘alert_level’
constant	msg	in	string	A custom message to be appended in the log/alert
signal	rx	in	std_logic	The UART BFM reception signal. Must be connected to the UART DUT ‘tx’ port.
signal	terminate_loop	in	std_logic	External control of loop termination to e.g. stop expect procedure prematurely
constant	max_receptions	in	natural	The maximum number of bytes received before the expected data must be received. Exceeding this limit results in an alert with severity ‘alert_level’. Setting this value to 0 will be interpreted as no limit. Default value is 1
constant	timeout	in	time	The maximum time to pass before the expected data must be received. Exceeding this limit results in an alert with severity ‘alert_level’. Setting this value to 0 will be interpreted as no timeout. Default value is the BFM config timeout.
constant	alert_level	in	t_alert_level	Sets the severity for the alert. Default value is ERROR.
constant	config	in	t_uart_bfm_config	Configuration of BFM behavior and restrictions. Default value is C_UART_BFM_CONFIG_DEFAULT.
constant	scope	in	string	Describes the scope from which the log/alert originates. Default value is C_BFM_SCOPE (“UART BFM”).
constant	msg_id_panel	in	t_msg_id_panel	Controls verbosity within a specified scope. Default value is shared_msg_id_panel.

-- Examples:
uart_expect(x"3B", "Expect data on UART RX", rx, terminate_signal, 1, 0 ns);
uart_expect(x"3B", "Expect data on UART RX", rx, terminate_signal, 1, 0 ns, ERROR, C_UART_BFM_CONFIG_DEFAULT, C_SCOPE, shared_msg_id_panel);

-- Suggested usage (requires local overload, see 'Local BFM overloads' section):
uart_expect(C_CR_BYTE, "Expecting carriage return");
uart_expect(C_CR_BYTE, "Expecting carriage return", C_TIMEOUT, C_MAX_RECEPTIONS);

Local BFM overloads

A good approach for better readability and maintainability is to make simple, local overloads for the BFM procedures in the TB process. This allows calling the BFM procedures with the key parameters only, e.g.

uart_transmit(C_ASCII_A, "Transmitting ASCII A");

rather than

uart_transmit(C_ASCII_A, "Transmitting ASCII A", tx, C_UART_CONFIG_LOCAL, C_SCOPE, shared_msg_id_panel);

By defining the local overload as e.g.

procedure uart_transmit(
  constant data_value : in std_logic_vector;
  constant msg        : in string) is
begin
  uart_transmit(data_value,           -- Keep as is
                msg,                  -- Keep as is
                tx,                   -- Signal must be visible in local process scope
                C_UART_CONFIG_LOCAL,  -- Use locally defined configuration or C_UART_CONFIG_DEFAULT
                C_SCOPE,              -- Use the default
                shared_msg_id_panel); -- Use global, shared msg_id_panel
end procedure;

Using a local overload like this also allows the following – if wanted:

Set up defaults for constants. May be different for two overloads of the same BFM
Apply dedicated message ID panel to allow dedicated verbosity control

Local BFM configuration

The UART BFM requires that a local configuration is declared in the testbench and used in the BFM procedure calls. The default BFM configuration is defined with a clock period of -1 ns so that the BFM can detect and alert the user that the configuration has not been set.

Defining a local UART BFM configuration::

constant C_UART_CONFIG_LOCAL : t_uart_bfm_config := (
  bit_time                              => C_UART_BIT_TIME,
  num_data_bits                         => 8,
  idle_state                            => '1',
  num_stop_bits                         => STOP_BITS_ONE,
  parity                                => PARITY_ODD,
  timeout                               => 0 ns,
  timeout_severity                      => error,
  num_bytes_to_log_before_expected_data => 10,
  match_strictness                      => MATCH_EXACT,
  id_for_bfm                            => ID_BFM,
  id_for_bfm_wait                       => ID_BFM_WAIT,
  id_for_bfm_poll                       => ID_BFM_POLL,
  id_for_bfm_poll_summary               => ID_BFM_POLL_SUMMARY,
  error_injection                       => C_BFM_ERROR_INJECTION_INACTIVE
);

Compilation

This BFM package may only be compiled with VHDL-2008 or newer. It is dependent on the Utility Library, which is only compatible with VHDL-2008 or newer.
After UVVM-Util has been compiled, the BFM package can be compiled into any desired library.
See Essential Mechanisms - Compile Scripts for information about compile scripts.

Simulator compatibility and setup

See Prerequisites for a list of supported simulators.
For required simulator setup see UVVM-Util Simulator compatibility and setup.

Additional Documentation

For additional documentation on the UART protocol, please see the UART specification.

Important

This is a simplified Bus Functional Model (BFM) for UART TX and RX.
The given BFM complies with the basic UART protocol and thus allows a normal access towards a UART interface.
This BFM is not a UART protocol checker.
For a more advanced BFM please contact UVVM support at info@uvvm.org

VVC

VVC functionality is implemented in uart_vvc.vhd
For general information see VVC Framework - Essential Mechanisms.

Entity

Generics

Name	Type	Default	Description
GC_DATA_WIDTH	natural	8	Bits in the UART byte. Note that this will initialize num_data_bits in the BFM configuration and override the setting in GC_UART_CONFIG.
GC_INSTANCE_IDX	natural	1	Instance number to assign the VVC
GC_UART_CONFIG	t_uart_bfm_config	C_UART_BFM_CONFIG_DEFAULT	Configuration for the UART BFM
GC_CMD_QUEUE_COUNT_MAX	natural	C_CMD_QUEUE_COUNT_MAX	Absolute maximum number of commands in the VVC command queue
GC_CMD_QUEUE_COUNT_THRESHOLD	natural	C_CMD_QUEUE_COUNT_THRESHOLD	An alert will be generated when reaching this threshold to indicate that the command queue is almost full. The queue will still accept new commands until it reaches GC_CMD_QUEUE_COUNT_MAX.
GC_CMD_QUEUE_COUNT_THRESHOLD_SEVERITY	t_alert_level	C_CMD_QUEUE_COUNT_THRESHOLD_SEVERITY	Alert severity which will be used when command queue reaches GC_CMD_QUEUE_COUNT_THRESHOLD
GC_RESULT_QUEUE_COUNT_MAX	natural	C_RESULT_QUEUE_COUNT_MAX	Maximum number of unfetched results before result_queue is full
GC_RESULT_QUEUE_COUNT_THRESHOLD	natural	C_RESULT_QUEUE_COUNT_THRESHOLD	An alert will be issued if result queue exceeds this count. Used for early warning if result queue is almost full. Will be ignored if set to 0.
GC_RESULT_QUEUE_COUNT_THRESHOLD_SEVERITY	t_alert_level	C_RESULT_QUEUE _COUNT_THRESHOLD_SEVERITY	Severity of alert to be initiated if exceeding GC_RESULT_QUEUE_COUNT_THRESHOLD

Signals

Object	Name	Dir.	Type	Description
signal	uart_vvc_rx	in	std_logic	UART VVC RX signal
signal	uart_vvc_tx	inout	std_logic	UART VVC TX signal

Configuration Record

vvc_config accessible via shared_uart_vvc_config

Record element	Type	Default	Description
inter_bfm_delay	t_inter_bfm_delay	C_UART_INTER_BFM_DELAY_DEFAULT	Delay between any requested BFM accesses towards the DUT. TIME_START2START: Time from a BFM start to the next BFM start (a TB_WARNING will be issued if access takes longer than TIME_START2START). TIME_FINISH2START: Time from a BFM end to the next BFM start. Any insert_delay() command will add to the above minimum delays, giving for instance the ability to skew the BFM starting time.
cmd_queue_count_max	natural	C_CMD_QUEUE_COUNT_MAX	Maximum pending number in command queue before queue is full. Adding additional commands will result in an ERROR.
cmd_queue_count_threshold	natural	C_CMD_QUEUE_COUNT_THRESHOLD	An alert will be issued if command queue exceeds this count. Used for early warning if command queue is almost full. Will be ignored if set to 0.
cmd_queue_count_threshold_severity	t_alert_level	C_CMD_QUEUE_COUNT_THRESHOLD_SEERITY	Severity of alert to be initiated if exceeding cmd_queue_count_threshold
result_queue_count_max	natural	C_RESULT_QUEUE_COUNT_MAX	Maximum number of unfetched results before result_queue is full
result_queue_count_threshold	natural	C_RESULT_QUEUE_COUNT_THRESHOLD	An alert will be issued if result queue exceeds this count. Used for early warning if result queue is almost full. Will be ignored if set to 0.
result_queue_count_threshold_severity	t_alert_level	C_RESULT_QUEUE_COUNT_THRESHOLD_SEVERITY	Severity of alert to be initiated if exceeding result_queue_count_threshold
bfm_config	t_uart_bfm_config	C_UART_BFM_CONFIG_DEFAULT	Configuration for the UART BFM
msg_id_panel	t_msg_id_panel	C_VVC_MSG_ID_PANEL_DEFAULT	VVC dedicated message ID panel. See Scope of Verbosity Control for how to use verbosity control.
error_injection	t_vvc_error_injection	C_VVC_ERROR_INJECTION_INACTIVE	Record to set up the error injection policy in the BFM procedure calls
bit_rate_checker	t_bit_rate_checker	C_BIT_RATE_CHECKER_DEFAULT	Configure the UART property checker behavior
unwanted_activity_severity	t_alert_level	C_UNWANTED_ACTIVITY_SEVERITY	Severity of alert to be issued if unwanted activity on the DUT outputs is detected. It is enabled with ERROR severity by default.

Note

cmd/result queue parameters in the configuration record are unused and will be removed in v3.0, use instead the entity generic constants.

The configuration record can be accessed from the Central Testbench Sequencer through the shared variable array, e.g.

shared_uart_vvc_config(RX, C_VVC_IDX).inter_bfm_delay.delay_in_time := 10 ms;
shared_uart_vvc_config(TX, C_VVC_IDX).bfm_config.num_data_bits := 8;

t_vvc_error_injection

Default value for the record is C_VVC_ERROR_INJECTION_INACTIVE.

Record element	Type	Default	Description
parity_bit_error_prob	real	-1.0	The probability that the VVC will request a parity_bit_error when calling a BFM transmission procedure. (See t_uart_bfm_config)
stop_bit_error_prob	real	-1.0	The probability that the VVC will request a stop_bit_error when calling a BFM transmission procedure. (See t_uart_bfm_config)

Note

A value of 1.0 means every transmission should have this error injection, whereas 0.0 means error injection is turned off. Anything in between means randomization with the given probability.
The error_injection config in the VVC config will override any error injection specified in the BFM config, unless set to -1.0 (default) in which case the BFM config error injection setting will be used.

For more information on error injection, please see Protocol Aware Error Injection.

t_bit_rate_checker

Default value for the record is C_BIT_RATE_CHECKER_DEFAULT.

Record element	Type	Default	Description
enable	boolean	false	Enables or disables the complete bit rate checker
min_period	time	0.0	The minimum allowed bit period for any bit (any bit level change to the next)
alert_level	t_alert_level	ERROR	Alert generated if min_period is violated

For more information on property checking, please see Controlling Property Checkers.

Status Record

vvc_status accessible via shared_uart_vvc_status

The current status of the VVC can be retrieved during simulation. This is achieved by reading from the shared variable from the test sequencer. The record contents can be seen below:

Record element	Type	Description
current_cmd_idx	natural	Command index currently running
previous_cmd_idx	natural	Previous command index to run
pending_cmd_idx	natural	Pending number of commands in the command queue

Methods

All VVC procedures are defined in vvc_methods_pkg.vhd (dedicated to this VVC).
See Common VVC Methods for procedures which are common to all VVCs.
It is also possible to send a multicast to all instances of a VVC with ALL_INSTANCES as parameter for vvc_instance_idx.
All parameters in brackets are optional.

uart_transmit()

Adds a transmit command to the UART TX VVC executor queue, which will run as soon as all preceding commands have completed. It
has two variants using either just data for a basic single transaction, or num_words + randomization for a more advanced version.
When the basic transmit command is scheduled to run, the executor calls the BFM uart_transmit() procedure. This
procedure scan only be called using the UART TX channel, i.e. setting ‘channel’ to ‘TX’.
When the more advanced randomization command is applied, the basic BFM uart_transmit() transaction is executed num_words times
with new random data each time - according to the given randomization profile. Current defined randomization profiles are:
RANDOM: Standard uniform random. This is provided as an example.
Errors may be injected depending on the ‘config.error_injection’ sub-record.

uart_transmit(VVCT, vvc_instance_idx, channel, data, msg, [scope])
uart_transmit(VVCT, vvc_instance_idx, channel, num_words, randomisation, msg, [scope])

Object	Name	Dir.	Type	Description
signal	VVCT	inout	t_vvc_target_record	VVC target type compiled into each VVC in order to differentiate between VVCs
constant	vvc_instance_idx	in	integer	Instance number of the VVC
constant	channel	in	t_channel	The VVC channel of the VVC instance
constant	data	in	std_logic_vector	The data value to be transmitted
constant	num_words	in	natural	Number of times the procedure is called to send new random data words
constant	randomisation	in	t_randomisation	Randomization profile
constant	msg	in	string	A custom message to be appended in the log/alert
constant	scope	in	string	Describes the scope from which the log/alert originates. Default value is C_VVC_CMD_SCOPE_DEFAULT.

-- Examples:
uart_transmit(UART_VVCT, 0, TX, x"AF", "Sending data to DUT UART instance 0", C_SCOPE);
uart_transmit(UART_VVCT, 0, TX, 5, RANDOM, "Sending 5 random bytes to DUT UART instance 0");

uart_receive()

Adds a receive command to the UART RX VVC executor queue, which will run as soon as all preceding commands have completed. When the command is scheduled to run, the executor calls the BFM uart_receive() procedure.

The received data from DUT will not be returned in this procedure call since it is non-blocking for the sequencer/caller, but the received data will be stored in the VVC for a potential future fetch (see example with fetch_result below). This procedure can only be called using the UART RX channel, i.e. setting ‘channel’ to ‘RX’. If the data_routing is set to TO_SB, the received data will be sent to the UART VVC dedicated scoreboard where it will be checked against the expected value (provided by the testbench).

uart_receive(VVCT, vvc_instance_idx, channel, [data_routing,] msg, [alert_level, [scope]])

Object	Name	Dir.	Type	Description
signal	VVCT	inout	t_vvc_target_record	VVC target type compiled into each VVC in order to differentiate between VVCs
constant	vvc_instance_idx	in	integer	Instance number of the VVC
constant	channel	in	t_channel	The VVC channel of the VVC instance
constant	data_routing	in	t_data_routing	Selects the destination of the read data
constant	msg	in	string	A custom message to be appended in the log/alert
constant	alert_level	in	t_alert_level	Unused. DEPRECATED
constant	scope	in	string	Describes the scope from which the log/alert originates. Default value is C_VVC_CMD_SCOPE_DEFAULT.

-- Examples:
uart_receive(UART_VVCT, 0, RX, "Receiving from DUT UART instance 0");
uart_receive(UART_VVCT, 0, RX, TO_SB, "Receiving data from DUT UART instance 0 and passing on to Scoreboard", ERROR, C_SCOPE);

-- Example with fetch_result() call: Result is placed in v_result
variable v_cmd_idx : natural;                       -- Command index for the last receive
variable v_result  : work.vvc_cmd_pkg.t_vvc_result; -- Result from receive.
...
uart_receive(UART_VVCT, 0, RX, "Receiving from DUT UART instance 0");
v_cmd_idx := get_last_received_cmd_idx(UART_VVCT, 0, RX);
await_completion(UART_VVCT, 0, RX, v_cmd_idx, 1 us, "Wait for receive to finish");
fetch_result(UART_VVCT, 0, RX, v_cmd_idx, v_result, "Fetching result from receive operation");

Hint

t_vvc_result is defined in the corresponding vvc_cmd_pkg.vhd for the VIP.

uart_expect()

Adds an expect command to the UART RX VVC executor queue, which will run as soon as all preceding commands have completed. When the command is scheduled to run, the executor calls BFM uart_expect() procedure. The uart_expect() procedure will perform a receive operation, then check if the received data is equal to the expected data in the data parameter. If the received data is not equal to the expected data parameter, an alert with severity ‘alert_level’ will be issued. The received data will not be stored in this procedure. This procedure can only be called using the UART RX channel, i.e. setting ‘channel’ to ‘RX’.

uart_expect(VVCT, vvc_instance_idx, channel, data, msg, [max_receptions, [timeout, [alert_level, [scope]]]])

Object	Name	Dir.	Type	Description
signal	VVCT	inout	t_vvc_target_record	VVC target type compiled into each VVC in order to differentiate between VVCs
constant	vvc_instance_idx	in	integer	Instance number of the VVC
constant	channel	in	t_channel	The VVC channel of the VVC instance
constant	data	in	std_logic_vector	The expected data value to be received
constant	msg	in	string	A custom message to be appended in the log/alert
constant	max_receptions	in	natural	The maximum number of bytes received before the expected data must be received. Exceeding this limit results in an alert with severity ‘alert_level’. Setting this value to 0 will be interpreted as no limit. Default value is 1
constant	timeout	in	time	The maximum time to pass before the expected data must be received. Exceeding this limit results in an alert with severity ‘alert_level’. Setting this value to 0 will be interpreted as no timeout. Default value is the BFM config timeout.
constant	alert_level	in	t_alert_level	Sets the severity for the alert. Default value is ERROR.
constant	scope	in	string	Describes the scope from which the log/alert originates. Default value is C_VVC_CMD_SCOPE_DEFAULT.

-- Examples:
uart_expect(UART_VVCT, 0, RX, x"0D", "Expecting carriage return from DUT UART instance 0");
uart_expect(UART_VVCT, 0, RX, C_CR_BYTE, "Expecting carriage return from DUT UART instance 0", 5, 10 ms, ERROR, C_SCOPE);

Activity Watchdog

The VVCs support a centralized VVC activity register which the activity watchdog uses to monitor the VVC activities. The VVCs will register their presence to the VVC activity register at start-up, and report when ACTIVE and INACTIVE, using dedicated VVC activity register methods, and trigger the global_trigger_vvc_activity_register signal during simulations. The activity watchdog is continuously monitoring the VVC activity register for VVC inactivity and raises an alert if no VVC activity is registered within the specified timeout period.

Include activity_watchdog(num_exp_vvc, timeout, [alert_level, [msg]]) in the testbench to start using the activity watchdog. Note that setting the exact number of expected VVCs in the VVC activity register can be omitted by setting num_exp_vvc = 0.

More information can be found in Essential Mechanisms - Activity Watchdog.

Transaction Info

This VVC supports transaction info, a UVVM concept for distributing transaction information in a controlled manner within the complete testbench environment. The transaction info may be used in many different ways, but the main purpose is to share information directly from the VVC to a DUT model.

UART transaction info record fields. Transaction Type: t_base_transaction (BT) - accessible via **shared_uart_vvc_transaction_info.bt**
Info field	Type	Default	Description
operation	t_operation	NO_OPERATION	Current VVC operation, e.g. INSERT_DELAY, POLL_UNTIL, READ, WRITE
data	std_logic_vector(7 downto 0)	0x0	Data for UART receive or transmit transaction
vvc_meta	t_vvc_meta	C_VVC_META_DEFAULT	VVC meta data of the executing VVC command
-> msg	string	“”	Message of executing VVC command
-> cmd_idx	integer	-1	Command index of executing VVC command
transaction_status	t_transaction_status	INACTIVE	Set to INACTIVE, IN_PROGRESS, FAILED or SUCCEEDED during a transaction
error_info	t_error_info	C_ERROR_INFO_DEFAULT	Error injection status
-> parity_bit_error	boolean	false	Status of the parity bit error injection
-> stop_bit_error	boolean	false	Status of the stop bit error injection

More information can be found in Essential Mechanisms - Distribution of Transaction Info.

Scoreboard

This VVC has built in Scoreboard functionality where data can be routed by setting the TO_SB parameter in supported method calls, i.e. uart_receive(). Note that the data is only stored in the scoreboard and not accessible with the fetch_result() method when the TO_SB parameter is applied. The UART scoreboard is accessible from the testbench as a shared variable UART_VVC_SB, located in the vvc_methods_pkg.vhd, e.g.

UART_VVC_SB.add_expected(C_UART_VVC_IDX, v_expected, "Adding expected");

See the Bitvis VIP Scoreboard for a complete list of available commands and additional information. All of the listed Generic Scoreboard commands are available for the UART VVC scoreboard using the UART_VVC_SB.

Unwanted Activity Detection

This VVC supports detection of unwanted activity from the DUT. This mechanism will give an alert if the DUT generates any unexpected bus activity. It assures that no data is output from the DUT when it is not expected, i.e. read/receive/check/expect VVC methods are not called. Once the VVC is inactive, it starts to monitor continuously on the DUT outputs. When unwanted activity is detected, the VVC issues an alert.

The unwanted activity detection can be configured from the central testbench sequencer, where the severity of alert can be changed to a different value. To disable this feature in the testbench, e.g.

shared_uart_vvc_config(RX, C_VVC_INDEX).unwanted_activity_severity := NO_ALERT;

For UART VVC, the unwanted activity detection is enabled by default with severity ERROR.

Note

This feature is only implemented on uart_rx_vvc.

More information can be found in Essential Mechanisms - Unwanted Activity Detection.

Compilation

The UART VVC must be compiled with VHDL-2008 or newer. It is dependent on the following libraries:

UVVM Utility Library (UVVM-Util)

UVVM VVC Framework

Bitvis VIP Scoreboard

UART BFM

Before compiling the UART VVC, assure that uvvm_util, uvvm_vvc_framework and bitvis_vip_scoreboard have been compiled.

See Essential Mechanisms - Compile Scripts for information about compile scripts.

Compile order for the UART VVC
Compile to library	File	Comment
bitvis_vip_uart	uart_bfm_pkg.vhd	UART BFM
bitvis_vip_uart	transaction_pkg.vhd	UART transaction package with DTT types, constants, etc.
bitvis_vip_uart	vvc_cmd_pkg.vhd	UART VVC command types and operations
bitvis_vip_uart	monitor_cmd_pkg.vhd	UART Monitor package. Only include this file if you intend to use Monitor.
bitvis_vip_uart	../uvvm_vvc_framework/src_target_dependent/td_target_support_pkg.vhd	UVVM VVC target support package, compiled into this VVC library
bitvis_vip_uart	../uvvm_vvc_framework/src_target_dependent/td_vvc_framework_common_methods_pkg.vhd	Common UVVM framework methods compiled into the this VVC library
bitvis_vip_uart	vvc_sb_pkg.vhd	UART VVC scoreboard
bitvis_vip_uart	vvc_methods_pkg.vhd	UART VVC methods
bitvis_vip_uart	../uvvm_vvc_framework/src_target_dependent/td_queue_pkg.vhd	UVVM queue package for this VVC
bitvis_vip_uart	../uvvm_vvc_framework/src_target_dependent/td_vvc_entity_support_pkg.vhd	UVVM VVC entity support compiled into this VVC library
bitvis_vip_uart	uart_rx_vvc.vhd	UART RX VVC
bitvis_vip_uart	uart_tx_vvc.vhd	UART TX VVC
bitvis_vip_uart	uart_vvc.vhd	UART VVC wrapper for the TX and RX VVCs
bitvis_vip_uart	uart_monitor.vhd	UART Monitor. Only include this file if you intend to use Monitor.
bitvis_vip_uart	vvc_context.vhd	UART VVC context file

Simulator compatibility and setup

See Prerequisites for a list of supported simulators.
For required simulator setup see UVVM-Util Simulator compatibility and setup.

Additional Documentation

For additional documentation on the UART protocol, please see the UART specification.

Important

This is a simplified Verification IP (VIP) for UART TX and RX.
The given VIP complies with the basic UART protocol and thus allows a normal access towards a UART interface.
This VIP is not a UART protocol checker.
For a more advanced VIP please contact UVVM support at info@uvvm.org

Monitor

Entity

Generics

Name	Type	Default	Description
GC_INSTANCE_IDX	natural	1	Instance number to assign the VVC
GC_MONITOR_CONFIG	t_uart_monitor_config	C_UART_MONITOR_CONFIG_DEFAULT	Configuration of the UART monitor, both channels get initiated with this configuration

Signals

Object	Name	Dir.	Type	Description
signal	uart_dut_rx	in	std_logic	Input of DUTs UART RX signal.
signal	uart_dut_tx	in	std_logic	Input of DUTs UART TX signal.

Configuration Record

t_uart_monitor_config accessible via shared_uart_monitor_config

Default value for the record is C_UART_MONITOR_CONFIG_DEFAULT.

Record element	Type	Default	Description
scope_name	string	“set scope name”	Describes the scope from which the log/alert originates.
msg_id_panel	t_msg_id_panel	C_UART_MONITOR_MSG_ID_PANEL_DEFAULT	Monitor dedicated message ID panel. See Scope of Verbosity Control for how to use verbosity control.
interface_config	t_uart_interface_config	C_UART_MONITOR_INTERFACE_CONFIG_DEFAULT	The configuration for the interface
transaction_display_time	time	0 ns	After this amount of time operation is set to NO_OPERATION and transaction_status is set to INACTIVE if a new transaction is not received. If set to 0 ns, operation and transaction_status will be unchanged until the next transfer is started.

The configuration record can be accessed from the Central Testbench Sequencer through the shared variable array, e.g.

shared_uart_monitor_config(TX, C_MONITOR_IDX).msg_id_panel := new_msg_id_panel;
shared_uart_monitor_config(TX, C_MONITOR_IDX).interface_config.num_data_bits := 8;

t_uart_interface_config

Default value for the record is C_UART_MONITOR_INTERFACE_CONFIG_DEFAULT.

Record element	Type	Default	Description
bit_time	time	0 ns	The time it takes to transfer one bit
num_data_bits	natural range 7 to 8	8	Number of data bits to send per transmission
parity	t_parity	PARITY_ODD	Transmission parity bit
num_stop_bits	t_stop_bits	STOP_BITS_ONE	Number of stop-bits to use per transmission

Transaction info

All transaction information from the UART Monitor is accessible via shared_uart_monitor_transaction_info

The global trigger pulsed when UART Monitor transaction info is available is accessible via global_uart_monitor_transaction_trigger

An example of use of the global_uart_monitor_transaction and shared_uart_monitor_transaction_info is seen below. A process extracts the transaction info from the shared variable when the global signal is triggered.

p_monitor_tx : process
  variable v_transaction : t_uart_transaction;
begin
  wait until global_uart_monitor_transaction_trigger(TX, 1) = '1';

  if (shared_uart_monitor_transaction_info(TX, 1).bt.transaction_status = SUCCEEDED or
      shared_uart_monitor_transaction_info(TX, 1).bt.transaction_status = FAILED) then
    v_transaction := shared_uart_monitor_transaction_info(TX, 1).bt;
  end if;

  -- Processing received transaction
  ...

end process p_monitor_tx;

For more information on the type, please see VVC Transaction Info.

Message IDs

ID_FRAME_INITIATE: Logs start of UART frame
ID_MONITOR: Logs information about monitored transaction

Compilation

The UART Monitor must be compiled with VHDL-2008 or newer. It is dependent on the following libraries:

UVVM Utility Library (UVVM-Util)

UVVM VVC Framework

Bitvis VIP Scoreboard

UART BFM

Before compiling the UART Monitor, assure that uvvm_util, uvvm_vvc_framework and bitvis_vip_scoreboard have been compiled.

See Essential Mechanisms - Compile Scripts for information about compile scripts.

Compile order for the UART Monitor
Compile to library	File	Comment
bitvis_vip_uart	uart_bfm_pkg.vhd	UART BFM
bitvis_vip_uart	transaction_pkg.vhd	UART transaction package with DTT types, constants, etc.
bitvis_vip_uart	vvc_cmd_pkg.vhd	UART VVC command types and operations
bitvis_vip_uart	monitor_cmd_pkg.vhd	UART Monitor package
bitvis_vip_uart	../uvvm_vvc_framework/src_target_dependent/td_target_support_pkg.vhd	UVVM VVC target support package, compiled into this VVC library
bitvis_vip_uart	vvc_sb_pkg.vhd	UART VVC scoreboard
bitvis_vip_uart	vvc_methods_pkg.vhd	UART VVC methods
bitvis_vip_uart	uart_monitor.vhd	UART Monitor

Simulator compatibility and setup

See Prerequisites for a list of supported simulators.
For required simulator setup see UVVM-Util Simulator compatibility and setup.

Additional Documentation

For additional documentation on the UART protocol, please see the UART specification.

Note

Disclaimer: This IP and any part thereof are provided “as is”, without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and non-infringement. In no event shall the authors or copyright holders be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with this IP.