Enhanced Serial Communication Interface (eSCI)
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 21-39
A physical bus error (LIN bus is permanently stuck at a fixed value) sets several error flags. If the input is
permanently low, the eSCI sets the framing error (FE) flag in the eSCI status register. If the RXD input
remains at the same value for 15 cycles after a transmission starts, the LIN hardware sets the PBERR flag
in the LIN status register. A bit error can also occur.
21.4.10.5 LIN Setup
Since the eSCI is for general-purpose use, some of the settings are not applicable for LIN operation. The
following setup applies for most applications, regardless of which kind of LIN slave is addressed:
1. Enable the module by clearing the ESCIx_CR2[MDIS] bit to 0.
2. Enable transmit and receive by setting ESCIx_CR1[TE] = 1, ESCIx_CR1[RE] = 1.
3. Clear the data format bit (ESCIx_CR1[M] = 0) to select 8 data bits, and disable the parity bit
(PE = 0).
4. Use the LIN interrupts by clearing the interrupt enable bits: ESCIx_CR1[TIE],
ESCIx_CR1[TCIE], and ESCIx_CR1[RIE]. Select LIN mode by setting ESCIx_LCR[LIN] = 1.
5. Set the break character (ESCIx_CR2[BRK13] = 1) to comply with the LIN standard requirements.
The eSCI works when BRK13 = 0, but violates LIN 2.0.
6. Bit errors are commonly configured to: reset the LIN FSM, immediately stop bus transfers, and
suspend DMA requests until the BERR flag is cleared. Use the following bit settings to perform
these functions: ESCIx_LCR[LDBG] = 0, ESCIx_CR2[SBSTP] = 1, and ESCIx_CR2[BSTP] = 1.
7. Fast bit error detection provides superior error checking. Set ESCIx_CR2[FBR]; it is commonly
used with ESCIx_CR2[BESM13] = 1.
8. If available, enable a pulldown on the RX input. (If the transceiver fails, the RX pin does not float).
9. Enable the following error indicators NF, FE, BERR, STO, PBERR, CERR, CKERR, and OVFL.
10. Transmit a wake-up character on the LIN bus to activate the LIN slaves.
Other settings like baud rate, length of break character etc., depend on the LIN slaves to which the eSCI
is connected.
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