Visible to Intel only — GUID: kio1725472231854
Ixiasoft
Visible to Intel only — GUID: kio1725472231854
Ixiasoft
12.2.2. Example 2: Reading the Memory Clock Frequency for an Interface
The values in this example are for illustrative purposes and are obtained from an EMIF example design with DDR4 x32 + ECC running at 800MHz on the Agilex™ 7 FPGA E-Series 065B Development Kit - Premium. This configuration uses the Primary MC of the Primary IO96B.
The table below illustrates the construction of the data to be written to the CMD_REQ register for this request:
CMD_REQ [31:29]: CMD_TARGET_IP_TYPE |
CMD_REQ [28:24]: CMD_TARGET_IP_INSTANCE_ID |
CMD_REQ [23:16]: CMD_TYPE |
CMD_REQ [15:0]: CMD_OPCODE |
CMD_REQ [31:0]: |
0x1 (Primary MC on Primary IO96B) |
0x0 | 0x02 (CMD_GET_MEM_INFO) |
0x0003 (GET_MEMCLK_REQ_KHZ) |
0x2002_0003 |
This OPCODE requires CMD_PARAM_0 to be specified. DDR4 supports only one memory clock frequency, set CMD_PARAM_0=0x4 to indicate that we will read the clock frequency for current frequency set point.
Follow these steps to send the Command using the JAMB/AXI-Lite interface for the interface:
- Write to the CMD_PARAM_0(address=0x500_0438) with write_data=0x4.
- Write to the CMD_REQ(address=0x500_043c) with write_data=0x2002_0003.
- Read from CMD_RESPONSE_STATUS(address=0x500_045c) until you get the STATUS_COMMAND_RESPONSE_READY (Bit 0 of CMD_RESPONSE_STATUS register) equals to 1.
Expected read_data=0x0000_0001.
- Read from CMD_RESPONSE_DATA_0(address=0x500_0458).
Expected read_data=0x000c_3500.
- Clear the STATUS_COMMAND_RESPONSE_READY (Bit 0 of CMD_RESPONSE_STATUS register). Perform a Read-Modify-Write operation:
- Read from CMD_RESPONSE_STATUS register.
- Write_Data = Data in (a) & 0xffff_fffe (Change only bit 0).
- Write to address = 0x500_045c data= write_data from (b).