Ports

Table 1. APB Interconnect General Ports
Port Direction Clock Domain Description
clk Input Clock source for APB Interconnect core.
rst_n Input Active low asynchronous reset.
apb_eval Output clk The assertion of this signal indicates that the APB Interconnect core is in EVALUATION state. When this signal is asserted, APB Interconnect core evaluates and decides which master to be granted a request. When this signal is de-asserted, it means that APB Interconnect core has exited the EVALUATION state and is actively granting a request to one of the masters.
grant_o[No. of Master-1:0] Output clk This is a one-hot signal. The binary position of 1 in this signal indicates which master is being granted a request. For example,
  • grant_o = 4'b0001 means Master_0 is being granted a request.
  • grant_o = 10'b00_0010_0000 means Master_5 is being granted a request.
When grant_o is all-zeros, it means no master is being granted a request.
Table 2. APB Interconnect Master Interface Ports
Port Direction Clock Domain Description
s_apb_psel_i[No. of Master-1:0] Input clk APB select signal from the master, to request an APB transfer.
s_apb_penable_i[No. of Master-1:0] Input clk APB enable signal from the master, to indicate the start of the APB request.
s_apb_pwrite_i[No. of Master-1:0] Input clk APB write signal from the master, to indicate whether the APB request is a write or read request.
s_apb_paddr_i[No. of Master*Address Width-1:0] Input clk APB address signal from the master, which contains the location of the destination register.
s_apb_pwdata_i[No. of Master*Data Width-1:0] Input clk APB write data signal from the master, which contains the data content to be written into the destination register. This signal is only effective if APB write signal is 1.
s_apb_pwdata_par_i[No. of Master*(Data Width/8)-1:0] Input clk APB write data parity signal from the master, which contains the data parity of the APB write data. This signal is only effective if APB write signal is 1.
s_apb_prdata_o[No. of Master*Data Width-1:0] Output clk APB read data signal to the master, which contains data read from destination register (slave) as the result of APB read request. This signal is cycle accurate with APB ready signal.
s_apb_prdata_par_o[No. of Master*(Data Width/8)-1:0] Output clk APB read data parity signal to the master, which contains data parity from the slave as the result of APB read request. This signal is cycle accurate with APB read data and APB ready signal.
s_apb_pready_o[No. of Master-1:0] Output clk APB ready signal from the slave to the master. The assertion of this signal indicates that the active APB transfer has been completed.
s_apb_pslverr_o[No. of Master-1:0] Output clk APB error signal from the slave to the master. The assertion of this signal indicates that an error has occurred during the APB transfer.
s_apb_pstrb_i[No. of Master*(Data Width/8)-1:0] Input clk APB write strobe signal from the master. This signal enables the write request with byte resolution. Each bit of this signal correlates with a byte of APB write data.
For example, when APB write strobe is 4'b1001, both APB Write Data[31:24] and APB Write Data[7:0] are intended to be written to the Destination Register[31:24] and Destination Register[7:0], whereas APB Write Data[23:16] and APB Write Data[15:8] are not intended to be processed, result in Destination Register[23:16] and Destination Register[15:8] retaining their original content.
This signal is effective only during write request.
s_apb_pstrb_par_i[Number of Master-1:0] Input clk APB write strobe parity signal from the master, which is effective during write request only.
Table 3. APB Interconnect Slave Interface Ports
Port Direction Clock Domain Description
apb_psel_o Output clk APB select signal from the APB Interconnect core to the slave, to trigger an APB request.
apb_penable_o Output clk APB enable signal from APB Interconnect core to slave, to start an APB transfer at 1 clock cycle after APB select.
To comply with APB protocol, the APB Interconnect core evaluates the masters' APB enable at 1 clock cycle after the assertion of masters' APB select, to determine the start of the APB transfer. Refer to APB Interconnect Operations.
apb_pwrite_o Output clk APB write signal from the APB Interconnect core to the slave.
When this signal is 1, it refers to an APB write request.
When this signal is 0, it refers to an APB read request.
apb_paddr_o[Address Width-1:0] Output clk APB address from the APB Interconnect core to slave. Contains the address of the destination location.
apb_pwdata_o[Data Width-1:0] Output clk APB write data signal from the APB Interconnect core to the slave, contains data content to be written into destination registers. This signal is effective only during a write request.
apb_pwdata_par_
o[(DataWidth/8)-1:0]
Output clk APB write data parity signal from the APB Interconnect core to the slave, contains the data parity of the APB write data. This signal is only effective if an APB write signal is 1.
apb_pstrb_o[(Data Width/8)-1:0] Output clk APB write strobe signal from the APB Interconnect core to the slave. This signal enables the write request with byte resolution. Each bit of this signal correlates with a byte of the APB write data.
For example, when APB write strobe is 4'b1001, both APB Write Data[31:24] and APB Write Data[7:0] are intended to be written to the Destination Register[31:24] and Destination Register[7:0], whereas APB Write Data[23:16] and APB Write Data[15:8] are not intended to be processed, results in Destination Register[23:16] and Destination Register[15:8] retaining their original content.
This signal is effective only during a write request.
apb_pstrb_par_o Output clk APB write strobe parity signal from the APB Interconnect core to the slave, which is effective only during a write request.
apb_prdata_i[Data Width-1:0] Input clk APB read data signal from the slave to the APB Interconnect core which contains data read from the destination register (slave) as the result of an APB read request. This signal is cycle accurate with the APB ready signal.
apb_prdata_par_i[(Data Width/8)-1:0] Input clk APB read data parity signal from the slave to the APB Interconnect core which contains data parity from the slave as a result of APB read request. This signal is cycle accurate with APB read data and APB ready signal.
apb_pready_i Input clk APB ready signal from the slave to the APB Interconnect core. The assertion of this signal indicates that the active APB transfer has been completed.
apb_pslverr_i Input clk APB error signal from the slave to the APB Interconnect core. The assertion of this signal indicates that an error has occurred during the APB transfer.