HI.
I'm currently using an AFE sampling system with MC33665A and MC33774 to form a double-chain loopback structure. The MC33665A's PORT0 and PORT1 are configured as MADD0 and MADD1 respectively, and all commands are currently sent via MADD0. When I only connect the daisy chain between PORT0 and DC1, my communication is normal. However, when I also connect the daisy chain between PORT1 and DC2, I find that the 33774 cannot reply with a response frame. Why is this? I have confirmed that the PORT configuration of the 33665 is correct and that SYS_TPL_CFG.RESPCFG in the 33774 is set to 00 SAME mode.
I am currently using an AFE sampling system consisting of the MC33665A + MC33774 in a dual-ring loop configuration. I have configured PORT0 and PORT1 of the MC33665A as MADD0 and MADD1, respectively, and all commands are currently sent through MADD0.
When I connect only the daisy chain between PORT0 and DC1, communication works correctly. However, after I also connect the daisy chain between PORT1 and DC2, the MC33774 no longer responds when I send requests to it.
Why does this happen?
I have read back and verified that the MC33665 PORT configuration is correct, and I have configured SYS_TPL_CFG.RESPCFG = 00 (SAME mode) in the MC33774.
HI.
1. I want to know if it is necessary to reverse the allocation of DADD from the position where MADD=1?
2. My current SYS_PORT0_CFG configuration is TIMEOUT=0, CADD=1, MADD=0, PROTOCOL=1, ALLCHAINS=1, TERM=1, RX=1, EN=1
SYS_PORT1_CFG is configured with TIMEOUT=0, CADD=1, MADD=1, PROTOCOL=1, ALLCHAINS=1, TERM=1, RX=1, EN=1
Hello,
According to the AN13910 TPL Loopback Recommendation, when two MC33665A TPL ports are connected as a loopback ring, there are several configuration requirements that may cause the behavior you are seeing.
For a loopback configuration:
- We recommend assigning device addresses (DADD) in ascending order from one side of the ring and in reverse order from the loopback side (I do not see this in your image).
- If two ports are connected as loopback, one of the ports should have SYS_PORTx_CFG[RX] = 0 to avoid duplicate data entering the MC33665 buffer.
- In addition, one of the ports should have SYS_PORTx_CFG[ALLCHAINS] = 0. If both loopback ports accept ALLCHAINS commands, document states that this can cause signal conflicts and communication errors.
Could you please share the values of SYS_PORT0_CFG and SYS_PORT1_CFG (especially EN, RX, ALLCHAINS, MADD, and CADD)? That would help determine whether the loopback ports are configured according to the AN13910 recommendations.