Hello,
Currently I'm investigating in an unexpected behaviour during SPI loopback mode on the TMS570LS3137.
We have the following loopback test setup:
/* disable loopback mode */
IOLPBKTSTCR = 0x0;
/* Induce bit error (CTRL_BITERR=1) */
IOLPBKTSTCR |= 1<< 20;
/* select analog loopback (LPBKTYPE=1) */
IOLPBKTSTCR |= 1<<1;
/* enable loopback mode */
IOLPBKTSTCR |= 0xA00;
When the test is executed we see the following behavior:
- As expected, the BITERRFLG in SPIFLG register is set
- However, we can see that the Rx data == Tx data when running this test
- CTRL_BITERR description says: "Induces bit errors by inverting the value of the incoming data during loopback."
We would think that in this case the Rx data does not match the Tx data but instead is inverted.
Despite this description we are wondering why we see a match between Tx and Rx data during this test.
Is this behavior expected?
Many thanks,
Michael
