Tool/software:
Hi,
We are struggling with performing PRBS test.
We are using Xilinx/AMD JESD204c IP and JESD204PHY IP to connect to 4 DAC39J84.
On the FPGA side, we are configuring the JESD204PHY for PRBS as follows:
PHY 0 => GT_INTERFACE_SELECTOR(0x024) = 0x0 (Lane 0)
PHY 0 => TXPRBSSEL(0x0520) = 0x1 (PRBS-7 pattern)
On the DAC side, we are configuring the first DAC39J84 for PRBS as follows:
DAC 0 => config74 (0x4A) = 0x001E (disable JESD clock)
DAC 0 => config61 (0x3D) = 0x208E (PRBS-7 pattern)
DAC 0 => config27 (0x1B) = 0x0300 (route PRBS test out to ALARM pin, lane 0)
Initially ALARM pin was high and after these configurations, the status of ALARM pin was low - seems perfect.
But then we tried to change the DAC lane from lane 0 to lane 1, 2 and so on, but the status of ALARM pin remains low.
Assuming the ALARM pin status is latched, we power cycle the board, and this time start from lane 1 but the result was same, we got low on ALARM pin which should be high. We repeat the test changing the PRBS type to other patterns but still got low on ALARM pin, indicating the test is passed!.
We again power cycle the board, and this time, without doing any configuration to the JESD204 PHY, just configured the DAC39J84 for normal use, and without doing config74 and config61 settings just wrote 0x0300 to config27 register and this caused ALARM pin to go low.
How to carry out the PRBS test?
Thanks
dac39j84 configuration was as follows:
0x00, 0x0218
0x01, 0x0003
0x02, 0x2002
0x03, 0xF380
0x04, 0x00FF
0x05, 0xFFFF
0x06, 0xFFFF
0x0C, 0x0400
0x0D, 0x0400
0x0E, 0x0400
0x0F, 0x0400
0x10, 0x0000
0x11, 0x0000
0x12, 0x0000
0x13, 0x0000
0x14, 0x0000
0x15, 0x0000
0x16, 0x0000
0x17, 0x0000
0x18, 0x0000
0x19, 0x0000
0x1A, 0x0020
0x1B, 0x0000
0x1C, 0x0000
0x1D, 0x0000
0x1E, 0x1111
0x1F, 0x1140
0x20, 0x0000
0x21, 0x0000
0x22, 0x1B1B
0x23, 0xFFFF
0x24, 0x0000
0x25, 0x8000
0x26, 0x0000
0x2D, 0x0000
0x2E, 0xFFFF
0x2F, 0x0004
0x30, 0x0000
0x31, 0x0000
0x32, 0x0000
0x33, 0x0100
0x34, 0x0000
0x35, 0x0000
0x3B, 0xF800
0x3C, 0x0000
0x3D, 0x008E
0x3E, 0x0108
0x3F, 0x0000
0x46, 0x0044
0x47, 0x190A
0x48, 0x31C3
0x49, 0x0000
0x4A, 0x001E
0x4B, 0x1F00
0x4C, 0x1F07
0x4D, 0x0300
0x4E, 0x0F4F
0x4F, 0x1CC1
0x50, 0x0000
0x51, 0x00FF
0x52, 0x00FF
0x53, 0x0000
0x54, 0x00FF
0x55, 0x00FF
0x5C, 0x1111
0x5F, 0x0123
0x60, 0x0456
0x61, 0x0111
0x6D, 0x0000
0x6E, 0x0000
0x6F, 0x0000
0x70, 0x0000
0x71, 0x0000
0x72, 0x0000
0x73, 0x0000
0x74, 0x0000
0x75, 0x0000
0x76, 0x0000
0x77, 0x0000
0x78, 0x0000
0x79, 0x0000
0x7A, 0x0000
0x7B, 0x0000
0x7C, 0x0000
0x7D, 0x0000}
