The following table describes the port list for the AXI processor interface.
| Signal | I/O | Description |
|---|---|---|
| s_axi_aclk | I | AXI4-Lite clock. Range between 10 MHz and 300 MHz |
| s_axi_aresetn | I | Asynchronous active-Low reset |
| s_axi_awaddr[31:0] | I | Write address Bus |
| s_axi_awvalid | I | Write address valid |
| s_axi_awready | O | Write address acknowledge |
| s_axi_wdata[31:0] | I | Write data bus |
| s_axi_wstrb[3:0] | I | Strobe signal for the data bus byte lane |
| s_axi_wvalid | O | Write data valid |
| s_axi_wready | O | Write data acknowledge |
| s_axi_bresp[1:0] | O | Write transaction response |
| s_axi_bvalid | O | Write response valid |
| s_axi_bready | I | Write response acknowledge |
| s_axi_araddr[31:0] | I | Read address bus |
| s_axi_arvalid | I | Read address valid |
| s_axi_arready | O | Read address acknowledge |
| s_axi_rdata[31:0] | O | Read data output |
| s_axi_rresp[1:0] | O | Read data response |
| s_axi_rvalid | O | Read data/response valid |
| s_axi_rready | I | Read data acknowledge |
| pm_tick | I | Top level signal to read statistics counters; requires MODE_REG[30] (i.e., tick_reg_mode_sel) be set to 0. |
Additional information for the operation of the AXI4 bus is found in Arm AMBA AXI Protocol v2.0 Specification (Arm IHI 0022C).
As noted previously, the top level signal pm_tick can be used to
read statistics counters instead of the configuration register TICK_REG. In this
case, configuration register MODE_REG bit 30 (i.e.,
tick_reg_mode_sel) should be set to 0. If
tick_reg_mode_sel set to 1, tick_reg is used
to read the statistics counters.