C2K User’s Guide
5-50
Resources
USART Modem Control Register
The USART Modem Control Register controls the UART interface to a modem.
4
EVEN_PAR
0
Even Parity—selects even parity checking—even number of (1)s in
data plus parity, or odd parity—odd number of (1)s in data plus parity.
0 = odd parity
1 = even parity
3
PAR_EN
0
Parity Enable—enables parity checking, which generates and appends
a parity bit to each outgoing character and checks parity on each
incoming character.
0 = disable parity
1 = enable parity
2
STOP
0
Stop—sets the number of generated stop bits.
0 = 1 stop bit
1 = 1.5 stop bits for 5-bit character; otherwise,
2 stop bits
1 - 0
LENGTH
0b00
Length—sets the number of bits in each character.
0b00 = 5 bits
0b01 = 6 bits
0b10 = 7 bits
0b11 = 8 bits
Address offset:
USAR0x4
Access:
Write-only
Bit(s)
Field
Default
Description
7 - 5
RSVD
0b000
Reserved (read-only)
4
LOOPBACK
0
Loopback Mode—sets modem operation to loopback mode. In loop-
back mode, the serial transmit output is set to (1), the transmit shift reg-
ister is internally connected to the receive shift register, DTR is
connected to DSR, RTS is connected to CTS, OUT1 is connected to
RI, and OUT2 is connected to DCD.
0 = normal operation
1 = loopback operation
3
OUT2
0
Output 2—in loopback mode, the modem output is connected to the
Data Carrier Detect input.
2
OUT1
0
Output 1—in loopback mode, the modem output is connected to the
Ring Indicator input.
1
RTS
0
External Ready To Send—controls the RTS signal.
0 = RTS is set to (1)
1 = RTS is set to (0)
0
DTR
0
External Data Terminal Ready—controls the DTR signal.
0 = DRT is set to (1)
1 = DTR is set to (0)
Bit(s)
Field
Default
Description
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