TXSOM=B_0x0, CECEN=B_0x0, TXEOM=B_0x0
CEC control register
| CECEN | CEC enable The CECEN bit is set and cleared by software. CECEN = 1 starts message reception and enables the TXSOM control. CECEN = 0 disables the CEC peripheral, clears all bits of CEC_CR register and aborts any on-going reception or transmission. 0 (B_0x0): CEC peripheral is off. 1 (B_0x1): CEC peripheral is on. |
| TXSOM | Tx start of message TXSOM is set by software to command transmission of the first byte of a CEC message. If the CEC message consists of only one byte, TXEOM must be set before of TXSOM. Start-bit is effectively started on the CEC line after SFT is counted. If TXSOM is set while a message reception is ongoing, transmission starts after the end of reception. TXSOM is cleared by hardware after the last byte of the message is sent with a positive acknowledge (TXEND = 1), in case of transmission underrun (TXUDR = 1), negative acknowledge (TXACKE = 1), and transmission error (TXERR = 1). It is also cleared by CECEN = 0. It is not cleared and transmission is automatically retried in case of arbitration lost (ARBLST = 1). TXSOM can be also used as a status bit informing application whether any transmission request is pending or under execution. The application can abort a transmission request at any time by clearing the CECEN bit. Note: TXSOM must be set when CECEN = 1. TXSOM must be set when transmission data is available into TXDR. HEADER first four bits containing own peripheral address are taken from TXDR[7:4], not from CEC_CFGR.OAR that is used only for reception. 0 (B_0x0): No CEC transmission is on-going 1 (B_0x1): CEC transmission command |
| TXEOM | Tx end of message The TXEOM bit is set by software to command transmission of the last byte of a CEC message. TXEOM is cleared by hardware at the same time and under the same conditions as for TXSOM. Note: TXEOM must be set when CECEN = 1. TXEOM must be set before writing transmission data to TXDR. If TXEOM is set when TXSOM = 0, transmitted message consists of 1 byte (HEADER) only (PING message). 0 (B_0x0): TXDR data byte is transmitted with EOM = 0 1 (B_0x1): TXDR data byte is transmitted with EOM = 1 |