r6781-12 Conexant Systems, Inc., r6781-12 Datasheet - Page 23

• Manufacturer Part Number: r6781-12
• Description: Embedded Modem Family
• Manufacturer: Conexant Systems, Inc.

EmbeddedModem Family
D224ATLVDSC
Modem Control Register
7
0
(Addr = 4)
6
0
The Modem Control Register (MCR) controls the interface with the modem or
data set.
Bit 5-7:
LL
OUT2
OUT1
RTS
DTR
5
0
LL
4
Not used (always 0).
Local Loopback. When this bit is set to a logic 1, the
diagnostic mode is selected and the following occurs:
1.
2.
Output 2. When this bit is a logic 1, HINT is enabled. When
this bit is a logic 0, HINT is in the high impedance state.
Output 1. This bit is used in local loopback (see MCR4).
Request to Send. This bit controls the Request to Send (RTS)
function. When this bit is a logic 1, RTS is on. When this bit is
a logic 0, RTS is off.
Data Terminal Ready. This bit controls the Data Terminal
Ready (DTR) function. When this bit is a logic 1, DTR is on.
When this bit is a logic 0, DTR is off.
Conexant
Data written to the Transmit Holding Register will be
looped back to the Receiver Buffer Register.
The four modem control bits (CTS, DSR, RI, and DCD)
are internally connected to the four modem control
outputs (RTS, DTR, OUT1, and OUT2), respectively.
OUT2
3
OUT1
2
RTS
1
2.1 Hardware Interface
DTR
0
2-9