search

pulp-platform / pulp_soc

pulp_soc is the core building component of PULP based SoCs
Other
78 stars 81 forks source link

Reasoning for stdout constants during synthesis #83

Closed christian-lanius closed 2 years ago

christian-lanius commented 2 years ago

Hi everyone, I am implementing the pulpissimo project. I synthesize it with "SYNTHESIS" and "TARGET_SYNTHESIS" defined. This leads to the signals of s_stdout_bus to be forced to low in the soc_peripherals (specifically pready, pslverr and prdata ). I use genus as synthesis tool and it correctly then warns about the signals being multidriven. Can you expand on the reasoning why these signals are special and why they are pulled low?

Warning : Signal or variable has multiple drivers, including a constant driver. [CDFG2G-623]
        : 's_stdout_bus_pready' in module 'soc_peripherals_MEM_ADDR_WIDTH17_APB_ADDR_WIDTH32_APB_DATA_WIDTH32_NB_CORES0_NB_CLUSTERS0_EVNT_WIDTH8_NGPIO32_NPAD64_NBIT_PADCFG6_NBIT_PADMUX2_N_UART32h00000001_N_SPI32h00000001_N_I2C32h00000002_SIM_STDOUT0_apb_slave_APB_BUS_Slave_apb_eu_master_APB_BUS_Master_apb_hwpe_master_APB_BUS_Master_apb_debug_master_APB_BUS_Master_l2_rx_master_XBAR_TCDM_BUS_Master_l2_tx_master_XBAR_TCDM_BUS_Master_soc_fll_master_FLL_BUS_out_per_fll_master_FLL_BUS_out_cluster_fll_master_FLL_BUS_out' in file '/home/lanius/code/pulp/pulpissimo/.bender/git/checkouts/apb-b24fbe74bd47ac2e/src/apb_intf.sv' on line 26, column 38.
        : Some tools may not accept this HDL.

Kind regards Christian

bluewww commented 2 years ago

It's a oversight/bug. Currently, the fixes are pending in https://github.com/pulp-platform/pulp_soc/pull/81

christian-lanius commented 2 years ago

Thanks for the heads up!