AT32F421
Series Reference Manual
2022.11.11
Page 133
Rev 2.02
Figure 12-2 BFF and FERR detection in LIN mode
RX pin
RDBF/
FERR
Idle frame
frame0
BREAK
frame1
1 frame time
BFF
CASE1
:
BREAK frame occurring after idle frame
CASE2
:
BREAK frame occurring while a frame is being
received
RX pin
RDBF/
FERR
frame0
BREAK
frame1
BFF
1 frame time
2.
Smartcard mode:
Parameters configuration: SCMEN=1, LINEN=0, SLHDEN=0, IRDAEN=0, CLKEN=1, DBN=1,
PEN=1, and STOPBN[1: 0]=11.
The polarity, phase and pulse number of the clock can be configured by setting the CLKPOL,
CLKPHA and LBCP bits (Refer to Synchronous mode for details).
The assertion of the TDC flag can be delayed by setting the SCGT[7: 0] bit (guard time bit). The TDF
bit can be asserted high after the guard time counter reaches the value programmed in the SCGT[7:
0] bit.
The Smartcard is a single-wire half duplex communication protocol. The SCNACKEN bit is used to
select whether to send NACK when a parity error occurs. This is to indicate to the Smarcard that the
data has not been correctly received
Figure 12-3 Smartcard frame format
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
P
Start
bit
Without Parity error
:
Bit 7
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
P
Start
bit
With Parity error
:
Bit 7
Guard time
Guard time
3.
Infrared mode
:
Parameters configuration: IRDAEN=1, CLKEN=0, STOPBN[1: 0]=0, SCMEN=0 and SLHDEN=0.
The infrared low-power mode can be enabled by setting IRDALP=1. In normal mode the transmitted
pulse width is specified as 3/16 bit. In infrared low-power mode, the pulse width can be configurable.
And the ISDIV[7:0] bit can be used to achieve the desired low-power frequency.