XR17V254 Datasheet, PDF (46/70 Pages) Exar Corporation – 66MHZ PCI BUS QUAD UART WITH POWER MANAGEMENT SUPPORT

XR17V254
66MHZ PCI BUS QUAD UART WITH POWER MANAGEMENT SUPPORT
REV. 1.0.0
LCR[5]: TX and RX Parity Select
If the parity bit is enabled, LCR bit [5] selects the forced parity format.
• LCR bit [5] = logic 0, parity is not forced (default).
• LCR bit [5] = logic 1 and LCR bit [4] = logic 0, parity bit is forced to a logical 1for the transmit and receive
data.
• LCR bit [5] = logic 1 and LCR bit [4] = logic 1, parity bit is forced to a logical 0 for the transmit and receive
data.
TABLE 17: PARITY PROGRAMMING
LCR BIT [5] LCR BIT [4] LCR BIT [3]
PARITY SELECTION
X
X
0
No parity
0
0
1
Odd parity
0
1
1
Even parity
1
0
1
Force parity to mark, “1”
1
1
1
Forced parity to space, “0”
LCR[4]: TX and RX Parity Select
If the parity bit is enabled with LCR bit [3] set to a logic 1, LCR bit [4] selects the even or odd parity format.
• Logic 0 = ODD Parity is generated by forcing an odd number of logic 1’s in the transmitted character. The
receiver must be programmed to check the same format (default).
• Logic 1 = EVEN Parity is generated by forcing an even the number of logic 1’s in the transmitted character.
The receiver must be programmed to check the same format.
LCR[3]: TX and RX Parity Select
Parity or no parity can be selected via this bit. The parity bit is a simple way used in communications for data
integrity check. See Table 17 above for parity selection summary.
• Logic 0 = No parity.
• Logic 1 = A parity bit is generated during the transmission while the receiver checks for parity error of the
data character received.
LCR[2]: TX and RX Stop-bit Length Select
The length of stop bit is specified by this bit in conjunction with the programmed word length.
BIT [2]
0
1
1
WORD
LENGTH
5,6,7,8
5
6,7,8
STOP BIT LENGTH
(BIT TIME(S))
1 (default)
1-1/2
2
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