Cec Configuration Register (Cec_Cfgr) - ST STM32G0 1 Series Reference Manual

HDMI-CEC controller (CEC)
Bit 0 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: CEC peripheral is off.
1: CEC peripheral is on.
39.7.2

CEC configuration register (CEC_CFGR)

This register is used to configure the HDMI-CEC controller.
Address offset: 0x04
Reset value: 0x0000 0000
Caution: It is mandatory to write CEC_CFGR only when CECEN = 0.
31 30 29
LSTN
rw rw rw
15 14 13
Res. Res. Res. Res.
Bit 31 LSTN: Listen mode
LSTN bit is set and cleared by software.
0: CEC peripheral receives only message addressed to its own address (OAR). Messages
addressed to different destination are ignored. Broadcast messages are always received.
1: CEC peripheral receives messages addressed to its own address (OAR) with positive
acknowledge. Messages addressed to different destination are received, but without interfering with
the CEC bus: no acknowledge sent.
Bits 30:16 OAR[14:0]: Own addresses configuration
The OAR bits are set by software to select which destination logical addresses has to be considered
in receive mode. Each bit, when set, enables the CEC logical address identified by the given bit
position.
At the end of HEADER reception, the received destination address is compared with the enabled
addresses. In case of matching address, the incoming message is acknowledged and received. In
case of non-matching address, the incoming message is received only in listen mode (LSTN = 1),
but without acknowledge sent. Broadcast messages are always received.
Example:
OAR = 0b000 0000 0010 0001 means that CEC acknowledges addresses 0x0 and 0x5.
Consequently, each message directed to one of these addresses is received.
Bits 15:9 Reserved, must be kept at reset value.
Bit 8 SFTOP: SFT option bit
The SFTOPT bit is set and cleared by software.
0: SFT timer starts when TXSOM is set by software.
1: SFT timer starts automatically at the end of message transmission/reception.
1358/1390
28 27 26 25
rw rw rw rw
12 11 10 9
Res. Res. Res.
24 23 22
OAR[14:0]
rw rw rw
8 7 6
SFT BRDN LBPE
OP OGEN GEN
rw rw rw
RM0444 Rev 5
21 20 19 18
rw rw rw rw
5 4 3 2
BRE BRE RX
GEN STP TOL
rw rw rw rw
RM0444
17 16
rw rw
1 0
SFT[2:0]
rw rw