Receiver Timeout Register (Usart_Rtor) - STMicroelectronics STM32F05 series Reference Manual

RM0091
25.7.6

Receiver timeout register (USART_RTOR)

Address offset: 0x14
Reset value: 0x0000
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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
Bits 23:0 RTO[23:0]: Receiver timeout value
This bit-field gives the Receiver timeout value in terms of number of baud clocks.
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
chapter 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.
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.
Note: This register is reserved and forced by hardware to "0x00000000" when the Receiver
timeout feature is not supported. Please refer to
.
page 573
Universal synchronous asynchronous receiver transmitter (USART)
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BLEN[7:0]
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from the LEN character in the Prologue Field). It must be programmed only once per
received block.
Doc ID 018940 Rev 1
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RTO[15:0]
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Section 25.4: USART implementation on
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RTO[23:16]
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