The tested digital RTL design is an isolator (LPI q-channel based) for the AMBA APB3 protocol bus (rtl/apb_isolator_top.sv).
The composition of the PyUVM verification environment:
-apb_iso_base_test - basic test
-apb_iso_env_cfg - environment configuration
-apb_iso_env - environment
-dut_reset_agent - agent for the DUT process
-uvm_sequencer
-reset_driver
-reset_monitor
-slv_reset_agent - agent for resetting the slave APB3
-uvm_sequencer
-reset_driver
-reset_monitor
-mst_reset_agent - agent for resetting master APB3
-uvm_sequencer
-reset_driver
-reset_monitor
-lpi_master_agent - LPI_Q channel interface management agent
-uvm_sequencer
-lpi_master_driver
-lpi_monitor
-apb_master_agent - APB3 Master bus management agent
-uvm_sequencer
-apb_master_driver
-apb_monitor
-apb_slave_agent - APB3 slave bus management agent
-apb_slave_sequencer - non-standard sequencer, memory support is implemented
-apb_slave_driver
-uvm_tlm_fifo
-apb_monitor
-apb_iso_scoreboard - golden model
-apb_iso_cov_collector - functional coverage collector (using cocotb-coverage)
Verification environment scheme on PyUVM:
Each agent of the verification environment is assigned its own signals in the RTL wrapper (rtl/apb_isolator_top_wrapper.sv). This allows you to instantiate many identical agents in an environment. The names of the signals comparable to them are indexed by the serial number of the agent creation.
Used frameworks in the environment:
| Framework | Link |
|---|---|
| cocotb | https://github.com/cocotb/cocotb |
| PyUVM | https://github.com/pyuvm/pyuvm |
| pyvsc (constraint, randomize) | https://github.com/fvutils/pyvsc |
| cocotb_coverage (functional coverage) | https://cocotb-coverage.readthedocs.io/en/latest/ |
| debugpy (Python debugger in vscode) | https://github.com/microsoft/debugpy |
Setup this frameworks using python venv:
[user@pc /../pyuvm_primer]$ python -m venv venv
[user@pc /../pyuvm_primer]$ source ./venv/bin/activate
[user@pc /../pyuvm_primer]$ pip install -r ./requirements.txtDocumentation of the standarts:
| Standart | Link |
|---|---|
| APB3 | https://web.eecs.umich.edu/~prabal/teaching/eecs373-f12/readings/ARM_AMBA3_APB.pdf |
| LPI q-channel | https://developer.arm.com/documentation/ihi0068/latest/ |
Start testing:
[user@pc /../pyuvm_primer]$ make Available Makefile Options:
| Option | Description |
|---|---|
| SIM | Default - icarus. Support Synopsys, Cadence. With Verilator don't work in this env, because X-state checking. |
| TEST_NAME | Default - apb_iso_all_random_reset_test. Available variant - apb_iso_server_test |
| PLUSARGS | +APB_ISO_ADDR_WIDTH=32 (APB address width) +APB_ISO_DATA_WIDTH=32 (APB data width) +num_pkts=1000 (iterations in apb_iso_all_random_reset_test) +has_cov=0 (coverage enable) +loglvl=DEBUG(log level) +pydebug=0 (python debug enable ) |
| WAVES | Default - 1. Support dump timing diagrams in vcd format |
| COCOTB_HDL_TIMEUNIT | Default 1ns |
| COCOTB_HDL_TIMEPRECISION | Default 1ps |
Using client-server testing:
In the test apb_iso_server_test.py the server is instantiated in run_phase. The server is waiting for the client to connect (apb_uart_client.py ) and commands from him. Simple commands such as starting a coroutine reset, random transaction on the master bus, and completing the simulation are implemented.
