B&B Electronics 1939STB manual Byte 5 UB3, Parity Setup

RS-232 Baud Rate Change cont’d.

Baud Change; Parity, word length, stop bits.

Byte 5 (UB3)

UB3 sets the LCR register on the UART

Table 14. Byte 5 (UB3)

Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
Divisor	Set	Set	Even	Parity	Stop	Word	Word
latch	break	parity	parity	enable	bits	length 1	length 0

Bit 7 = 1 allows baud rate divisor to be changed. 0 baud rate change is blocked.

Bit seven should not be set. The setting and resetting of this bit is handled internally.

Bit 6 = 1 forces the transmitter output to a logic 0 for alerting the remote receiver to a line break.

0 No break condition.

Bits 5, 4, 3 work together to set parity.

Table 15. Parity Setup

Bit 5	Bit 4	Bit 3	Parity Selection
X	X	0	No parity *
0	0	1	Odd parity
0	1	1	Even parity
1	0	1	Force parity “1”
1	1	1	Force parity “0”

* Setup Default Value.

1939STB4600 Manual 11

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