SPRUIV7B May 2022 – September 2023 AM620-Q1 , AM623 , AM625 , AM625-Q1 , AM625SIP
Only packet headers bits are protected by ECC in the FIFO RAMs. The ECC_ERR_CTRL1[31-0] ECC_ROW bit is used to activate a row address where force single-bit error or force double-bit error needs to be applied. ECC_ERR_CTRL2 [15-0] ECC_BIT1 is implemented to determine which bit of the header is flipped for an SEC error when the ECC_CRC_MODE bit is cleared in the CPSW_CONTROL_REG register. The ECC status registers return the RAM row address where the single or double-bit error has occured (ECC_ERR_STAT2[31-0] ECC_ROW) along with the bit position in the RAM data that is in error (ECC_ERR_STAT1[31-16] ECC_BIT1 value). Forcing double-bit errors in testing can cause indeterminate operation if multiple used packet header bits are flipped given that only single-bit errors are fixed by the ECC logic. Header bits 207 down to 200 are not currently used in the CPSW and may be used to test double bit errors without the possibility of requiring a reset for the switch to recover from the double bit error. No header bits are flipped when ECC_CRC_MODE is set to 1h. Either the RX_ECC_ERR_EN (enable receive ECC error operations) or the TX_ECC_ERR_EN (enable transmit ECC error operations) bits must be set in the CPSW_P0_CONTROL_REG register to test ECC header errors.
The header ECC code is stored in bits 255 down to 208. If any bit is flipped in the ECC code, the flipped bit will be corrected, but the index of the flipped bit will be reported as bit zero. This implies that when the aggregator reports that there is a SEC on bit 0, it can mean two things: either SEC on data bit 0 or SEC somewhere inside the ECC code. Any packet header with ECC error issues a pulse interrupt (ECC_PULSE_INTR) as does an ALE RAM ECC error.