Bitvis VIP Clock Generator

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VVC

VVC

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

Entity

Generics

Name	Type	Default	Description
GC_INSTANCE_IDX	natural	1	Instance number to assign the VVC
GC_CLOCK_NAME	string	“clk”	Name to assign the VVC
GC_CLOCK_PERIOD	time	10 ns	Clock period to assign the VVC
GC_CLOCK_HIGH_TIME	time	5 ns	Time of the clock cycle that is ‘1’. Value must be less than GC_CLOCK_PERIOD
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	clk	out	std_logic	VVC Clock signal

Configuration Record

vvc_config accessible via shared_clock_generator_vvc_config

Record element	Type	Default	Description
inter_bfm_delay	t_inter_bfm_delay	C_CLOCK_GENERATOR_INTER_BFM_DELAY_DEFAULT	Record parameter required by the VVC Framework, not applicable for this VVC
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_bfm_config	C_VOID_BFM_CONFIG	Record parameter required by the VVC Framework, not applicable for this VVC
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.
clock_name	string	“Set clock name”	Name of the VVC
clock_period	time	10 ns	Clock period
clock_high_time	time	5 ns	Time of the clock cycle that is ‘1’. Value must be less than clock_period

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_clock_generator_vvc_config(C_VVC_IDX).clock_period := 50 ns;

Status Record

vvc_status accessible via shared_clock_generator_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.

start_clock()

Adds a start_clock command to the Clock Generator VVC executor queue, which will run as soon as all preceding commands have completed. When the command is scheduled to run, the executor activates the clock generator process in the VVC.

start_clock(VVCT, vvc_instance_idx, 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	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:
start_clock(CLOCK_GENERATOR_VVCT, 1, "Start clock generator", C_SCOPE);

stop_clock()

Adds a stop_clock command to the Clock Generator VVC executor queue, which will run as soon as all preceding commands have completed. When the command is scheduled to run, the executor deactivates the clock generator process in the VVC after finishing the current clock cycle.

stop_clock(VVCT, vvc_instance_idx, 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	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:
stop_clock(CLOCK_GENERATOR_VVCT, 1, "Stop clock generator", C_SCOPE);

set_clock_period()

Adds a set_clock_period command to the Clock Generator VVC executor queue, which will run as soon as all preceding commands have completed. When the command is scheduled to run, the executor will change the clock period on the preceding rising clock edge. Note: the clock high time will have to be set using the set_clock_high_time() after setting a new clock period.

set_clock_period(VVCT, vvc_instance_idx, clock_period, 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	clock_period	in	time	Clock period
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:
set_clock_period(CLOCK_GENERATOR_VVCT, 1, 10 ns, "Change clock period to 10 ns", C_SCOPE);

set_clock_high_time()

Adds a set_clock_high_time command to the Clock Generator VVC executor queue, which will run as soon as all preceding commands have completed. When the command is scheduled to run, the executor changes the clock high time and the change will take effect from the next rising edge.

set_clock_high_time(VVCT, vvc_instance_idx, clock_high_time, 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	clock_high_time	in	time	Time of the clock cycle that is ‘1’. Value must be less than clock_period
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:
set_clock_high_time(CLOCK_GENERATOR_VVCT, 1, 6 ns, "Change the duty cycle to 60%", C_SCOPE);

Compilation

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

UVVM Utility Library (UVVM-Util)

UVVM VVC Framework

Before compiling the Clock Generator VVC, assure that uvvm_util and uvvm_vvc_framework have been compiled.

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

Compile order for the Clock Generator VVC
Compile to library	File	Comment
bitvis_vip_clock_generator	vvc_cmd_pkg.vhd	Clock Generator VVC command types and operations
bitvis_vip_clock_generator	../uvvm_vvc_framework/src_target_dependent/td_target_support_pkg.vhd	UVVM VVC target support package, compiled into this VVC library
bitvis_vip_clock_generator	../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_clock_generator	vvc_methods_pkg.vhd	Clock Generator VVC methods
bitvis_vip_clock_generator	../uvvm_vvc_framework/src_target_dependent/td_queue_pkg.vhd	UVVM queue package for this VVC
bitvis_vip_clock_generator	../uvvm_vvc_framework/src_target_dependent/td_vvc_entity_support_pkg.vhd	UVVM VVC entity support compiled into this VVC library
bitvis_vip_clock_generator	clock_generator_vvc.vhd	Clock Generator VVC
bitvis_vip_clock_generator	vvc_context.vhd	Clock Generator 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.

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.