RM0367 Rev 7 821/1043
RM0367 Universal synchronous/asynchronous receiver transmitter (USART/UART)
872
Note: RTOR can be written on the fly. If the new value is lower than or equal to the counter, the
RTOF flag is set.
This register is reserved and forced by hardware to “0x00000000” when the Receiver
timeout feature is not supported. Please refer to
Section 29.4: USART implementation on
page 766
.
29.8.7 USART request register (USART_RQR)
Address offset: 0x18
Reset value: 0x0000 0000
Bits 31:24 BLEN[7:0]: Block Length
This bit-field gives the Block length in Smartcard T=1 Reception. Its value equals the number
of information characters + the length of the Epilogue Field (1-LEC/2-CRC) - 1.
Examples:
BLEN = 0 -> 0 information characters + LEC
BLEN = 1 -> 0 information characters + CRC
BLEN = 255 -> 254 information characters + CRC (total 256 characters))
In Smartcard mode, the Block length counter is reset when TXE=0.
This bit-field can be used also in other modes. In this case, the Block length counter is reset
when RE=0 (receiver disabled) and/or when the EOBCF bit is written to 1.
Note: This value can be programmed after the start of the block reception (using the data
from the LEN character in the Prologue Field). It must be programmed only once per
received block.
Bits 23:0 RTO[23:0]: Receiver timeout value
This bit-field gives the Receiver timeout value in terms of number of bit duration.
In standard mode, the RTOF flag is set if, after the last received character, no new start bit is
detected for more than the RTO value.
In Smartcard mode, this value is used to implement the CWT and BWT. See Smartcard
section for more details.
In this case, the timeout measurement is done starting from the Start Bit of the last received
character.
Note: This value must only be programmed once per received character.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res.
151413121110987654321 0
Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. TXFRQ RXFRQ MMRQ SBKRQ ABRRQ
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