SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
In case of Private Write SDR commands, the payload length that needs to be specified is always equal to the number of data bytes sent to slave in Private Write transmission. If the payload specified is greater than slave’s capability, the data are simply ignored by slave.
In case of Private Read SDR commands slave is the device which normally decides how many bytes it is able to send and when the read transfer is terminated. This can also result from hardware architecture or from SETMRL CCC command sent earlier to the slave.
For simplified handling I3C design triggers the read abort procedure after receiving specified number of payload bytes. This matters in these transfer modes which send data bytes after one another. If one of these modes is used, the I3C_CMD0_FIFO[23-12] PL_LEN bit-field is interpreted as payload size that should not be reached during transfer rather than the actual number of bytes to be received. This applies only to read transfer from I3C devices.
Transmission | I3C_CMD0_FIFO[28-27] XMIT_MODE | I3C_DEV_IDn_RR0[9] IS_I3C (n = 0 to 11) | I3C_CMD0_FIFO[23-12] PL_LEN |
---|---|---|---|
I3C, NCA | 11 | 1 | Abort limit(1) |
I3C, Single | 00 | 1 | Abort limit(1) |
I3C, Multi-Static | 10 | 1 | Number of bytes to receive |
I3C, Multi-Incremental | 01 | 1 | Number of bytes to receive |