ST16C580
21
Rev. 1.22
LCR BIT-4:
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 data. The
receiver must be programmed to check the same
format. (normal default condition)
Logic 1 = EVEN Parity is generated by forcing an even
the number of logic 1’s in the transmitted. The receiver
must be programmed to check the same format.
LCR BIT-5:
If the parity bit is enabled, LCR BIT-5 selects the
forced parity format.
LCR BIT-5 = logic 0, parity is not forced (normal
default condition)
LCR BIT-5 = logic 1 and LCR BIT-4 = logic 0, parity bit
is forced to a logical 1 for 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.
LCR
Parity selection
Bit-5
Bit-4
Bit-3
X
0
No parity
0
1
Odd parity
0
1
Even parity
1
0
1
Force parity “1”
1
Forced parity “0”
LCR BIT-6:
When enabled the Break control bit causes a break
condition to be transmitted (the TX output is forced to
a logic 0 state). This condition exists until disabled by
setting LCR bit-6 to a logic 0.
Logic 0 = No TX break condition. (normal default
condition)
Logic 1 = Forces the transmitter output (TX) to a logic
0 for alerting the remote receiver to a line break
condition.
LCR BIT-7:
The internal baud rate counter latch and Enhance
Feature mode enable.
Logic 0 = Divisor latch disabled. (normal default
condition)
Logic 1 = Divisor latch and enhanced feature register
enabled.
Modem Control Register (MCR)
This register controls the interface with the modem or
a peripheral device.
MCR BIT-0:
Logic 0 = Force -DTR output to a logic 1. (normal
default condition)
Logic 1 = Force -DTR output to a logic 0.
MCR BIT-1:
Logic 0 = Force -RTS output to a logic 1. (normal
default condition)
Logic 1 = Force -RTS output to a logic 0.
Automatic RTS may be used for hardware flow control
by enabling EFR bit-6 (See EFR bit-6).
MCR BIT-2:
Logic 0 = Set -OP1 output to a logic 1. (normal default
condition)
Logic 1 = Set -OP1 output to a logic 0.
MCR BIT-3:
Logic 0 = Set -OP2 output to a logic 1. (normal default
condition)
Logic 1 = Set -OP2 output to a logic 0.
MCR BIT-4:
Logic 0 = Disable loop-back mode. (normal default
condition)
Logic 1 = Enable local loop-back mode (diagnostics).
MCR BIT-5:
Not used.
MCR BIT-6:
Logic 0 = Enable Modem receive and transmit input/
output interface. (normal default condition)
Logic 1 = Enable infrared IrDA receive and transmit