smc_padring

Mux SMC peripheral digital I/O onto chiplet pads.

Instantiates one gpio interface per pad behind an AXI-Lite demux whose error target returns DECERR with data 0xBADCAB1E outside the GPIO window. Assigns fixed pads to SPI, UART, I3C, I2C, AVSBus, the system timer, and the isolate-request, boot-stall and cool-reset pins; each function's enable drives the pad's LSIO select, which the gpio registers can disable. The pad mapping is combinational.

Parameters

Table 1. Parameters
Name	Type	Default	Description
`MAX_TRANS`	`int unsigned`	`1`	Maximum outstanding transactions of the demux and of each gpio interface.
`GPIO_INTF_BASE_ADDR`	`bit [gpio_pkg::AddrWidth-1:0]`	`32'h00000000`	Base address of the first GPIO interface; the demux decodes NumGpioWraps 16-byte slots from it.

Ports

Table 2. Ports
Name	Direction	Type	Description
`clk_i`	input	`logic`	SMC core clock for the GPIO register demux and the GPIO interfaces.
`rst_primary_ni`	input	`logic`	Primary reset, active-low, synchronized to clk_i; resets the demux and GPIO registers.
`rst_cold_stable_smc_clk_ni`	input	`logic`	Stable cold reset, active-low, synchronized to clk_i; while low, every GPIO pad is held in its default direction with the output disabled.
`test_en_i`	input	`logic`	DFT test-mode enable, active-high, passed to the demux and the gpio interfaces.
`scan_rst_ni`	input	`logic`	DFT scan reset, active-low; unused.
`axil_req_i`	input	`gpio_pkg::gpio_axil_req_t`	AXI-Lite Register Interface request.
`axil_resp_o`	output	`gpio_pkg::gpio_axil_resp_t`	AXI-Lite Register Interface response.
`spi_enable_i`	input	`logic`	Selects the SPI function on GPIO pads 0-10 and 54, active-high.
`spi_clk_i`	input	`logic`	Serial bit-rate clock driven onto GPIO 9.
`spi_txd_i`	input	`logic [7:0]`	Transmit data driven onto GPIO 0-7, one bit per pad.
`spi_cs_n_i`	input	`logic`	Chip select, active-low, driven onto GPIO 8.
`spi_cs_oe_n_i`	input	`logic`	Output enable for the chip-select pad (GPIO 8), active-low.
`spi_cs_ie_n_i`	input	`logic`	Input enable for the chip-select pad (GPIO 8), active-low.
`spi_clk_ie_n_i`	input	`logic`	Input enable for the SPI clock pad (GPIO 9), active-low.
`spi_clk_oe_n_i`	input	`logic`	Output enable for the SPI clock pad (GPIO 9), active-low.
`spi_dqs_ie_n_i`	input	`logic`	Input enable for the data-strobe pad (GPIO 10), active-low.
`spi_dqs_oe_n_i`	input	`logic`	Output enable for the data-strobe pad (GPIO 10), active-low; the pad drives zero when enabled.
`spi_dq_ie_n_i`	input	`logic [7:0]`	Input enables for the data pads (GPIO 0-7), active-low.
`spi_dq_oe_n_i`	input	`logic [7:0]`	Output enables for the data pads (GPIO 0-7), active-low.
`spi_rxd_o`	output	`logic [7:0]`	Receive data sampled from GPIO 0-7.
`spi_rxds_o`	output	`logic`	Read data strobe sampled from GPIO 10, used in DDR mode.
`spi_mem_rebar_oepad_i`	input	`logic`	Output enable for the SPI DQS loopback pad (GPIO 54), active-high.
`spi_mem_rebar_opad_i`	input	`logic`	Data driven onto the SPI DQS loopback pad (GPIO 54).
`spi_mem_rebar_iepad_i`	input	`logic`	Input enable for the SPI DQS loopback pad (GPIO 54), active-high.
`spi_mem_rebar_ipad_o`	output	`logic`	Value sampled from the SPI DQS loopback pad (GPIO 54).
`uart_enable_i`	input	`logic [smc_config_pkg::NumUart-1:0]`	Selects each UART's four pads, active-high, one bit per UART; UART u uses GPIO 11+4u (RX), 12+4u (TX), 13+4u (RTS) and 14+4u (CTS).
`uart_rx_o`	output	`logic [smc_config_pkg::NumUart-1:0]`	Receive data sampled from each UART's RX pad.
`uart_tx_i`	input	`logic [smc_config_pkg::NumUart-1:0]`	Transmit data driven onto each UART's TX pad.
`uart_rts_n_i`	input	`logic [smc_config_pkg::NumUart-1:0]`	Request-to-send, active-low, driven onto each UART's RTS pad.
`uart_cts_n_o`	output	`logic [smc_config_pkg::NumUart-1:0]`	Clear-to-send, active-low, sampled from each UART's CTS pad.
`chiplet_is_primary_i`	input	`logic`	Timer pad direction: high drives GPIO 55 and 56 from the timer inputs, low samples them.
`timer_sync_load_i`	input	`logic`	System timer sync-load, driven onto GPIO 55 on the primary chiplet.
`timer_cnt_credit_i`	input	`logic`	System timer count credit, driven onto GPIO 56 on the primary chiplet.
`timer_sync_load_o`	output	`logic`	System timer sync-load sampled from GPIO 55, used on a secondary chiplet.
`timer_cnt_credit_o`	output	`logic`	System timer count credit sampled from GPIO 56, used on a secondary chiplet.
`timer_gpio_enable_i`	input	`logic`	Selects the system timer function on GPIO 55 and 56, active-high.
`boot_stall_o`	output	`logic`	Boot-stall strap sampled from GPIO 57, not synchronized to clk_i.
`i3c_enable_i`	input	`logic [smc_config_pkg::NumI3c-1:0]`	Selects each I3C instance's SCL and SDA pads, active-high: GPIO 27-28 for instance 0, 63-64 for instance 1, and from 29 upward for the rest.
`i3c_scl_o`	output	`logic [smc_config_pkg::NumI3c-1:0]`	SCL sampled from each I3C instance's SCL pad.
`i3c_sda_o`	output	`logic [smc_config_pkg::NumI3c-1:0]`	SDA sampled from each I3C instance's SDA pad.
`i3c_scl_i`	input	`logic [smc_config_pkg::NumI3c-1:0]`	SCL value driven onto each I3C instance's SCL pad.
`i3c_scl_oen_i`	input	`logic [smc_config_pkg::NumI3c-1:0]`	Output enable for each SCL pad, active-low.
`i3c_sda_i`	input	`logic [smc_config_pkg::NumI3c-1:0]`	SDA value driven onto each I3C instance's SDA pad.
`i3c_sda_oen_i`	input	`logic [smc_config_pkg::NumI3c-1:0]`	Output enable for SDA IO pad (active low).
`i3c_sda_pp_i`	input	`logic [smc_config_pkg::NumI3c-1:0]`	Push-pull select for each SDA pad; high enables the SDA output whatever i3c_sda_oen_i is.
`i2c_enable_i`	input	`logic [smc_config_pkg::NumI2c-1:0]`	Selects each I2C instance's SCL, SDA, SMBus alert and SMBus suspend pads, active-high; instance i uses GPIO 37+4i to 40+4i.
`i2c_master_enable_i`	input	`logic [smc_config_pkg::NumI2c-1:0]`	Controller mode per I2C instance: the SMBus alert pad is sampled and the suspend pad driven; in target mode the directions reverse.
`i2c_scl_o`	output	`logic [smc_config_pkg::NumI2c-1:0]`	SCL sampled from each I2C instance's SCL pad.
`i2c_sda_o`	output	`logic [smc_config_pkg::NumI2c-1:0]`	SDA sampled from each I2C instance's SDA pad.
`i2c_smbus_n_o`	output	`logic [smc_config_pkg::NumI2c-1:0]`	SMBus suspend, active-low, sampled from the pad in target mode; zero in controller mode.
`i2c_smbus_alert_n_o`	output	`logic [smc_config_pkg::NumI2c-1:0]`	SMBus alert, active-low, sampled from the pad in controller mode; zero in target mode.
`i2c_scl_oen_i`	input	`logic [smc_config_pkg::NumI2c-1:0]`	Open-drain SCL control, active-low: low pulls the pad low, high releases it to the board pull-up.
`i2c_sda_oen_i`	input	`logic [smc_config_pkg::NumI2c-1:0]`	Open-drain SDA control, active-low: low pulls the pad low, high releases it to the board pull-up.
`i2c_smbus_n_i`	input	`logic [smc_config_pkg::NumI2c-1:0]`	SMBus suspend from the I2C core, active-low; in controller mode, low pulls the suspend pad low.
`i2c_smbus_alert_oe_i`	input	`logic [smc_config_pkg::NumI2c-1:0]`	In target mode, high pulls the SMBus alert pad low.
`avs_enable_i`	input	`logic`	Selects the AVSBus function on GPIO pads 49-51, active-high.
`avs_clock_i`	input	`logic`	AVSBus clock from the AVSBus controller, driven onto GPIO 49.
`avs_mdata_i`	input	`logic`	AVSBus controller-to-device data, driven onto GPIO 50.
`avs_sdata_o`	output	`logic`	AVSBus device-to-controller data, sampled from GPIO 51.
`rst_cool_ni`	input	`logic`	Cool reset for other chiplets, active-low; pulls GPIO 62 low while asserted and leaves it undriven otherwise.
`isolate_req_pin_o`	output	`logic`	Isolation request sampled from GPIO 53, not synchronized to clk_i.
`lsio_interface_select_o`	output	`logic [smc_pkg::NumGpioWraps-1:0]`	LSIO select per pad, high where a peripheral function claims the pad; also drives each gpio interface's select.
`core2pad_o`	output	`logic [smc_pkg::NumGpioWraps-1:0]`	Data driven to each pad by its gpio interface; zero during cold reset.
`core2pad_en_o`	output	`logic [smc_pkg::NumGpioWraps-1:0]`	Output enable for each pad, active-high; low during cold reset.
`pad2core_i`	input	`logic [smc_pkg::NumGpioWraps-1:0]`	Value received from each pad, not synchronized to clk_i.
`pad2core_en_o`	output	`logic [smc_pkg::NumGpioWraps-1:0]`	Input enable for each pad, active-high; the pad's default direction during cold reset.
`gpio_interrupt_o`	output	`logic [smc_pkg::NumGpioWraps-1:0]`	Interrupt from each gpio interface, active-high, registered on clk_i.