CD2231 Intel Corporation, CD2231 Datasheet - Page 121

• Manufacturer Part Number: CD2231
• Description: CD2231 Intelligent Two-channel Lan And Wan Communications Controller
• Manufacturer: Intel Corporation

8.4.4
8.4.4.1
8.4.4.2
Datasheet
Register Name: MSVR-RTS
Register Description: Modem Signal Value - RTS
Default Value: x’00
Access: Byte Read/Write
Register Name: MSVR-DTR
Register Description: Modem Signal Value - DTR
Default Value: x’00
Access: Byte Read/Write
DSR
DSR
Bit 7
Bit 7
Bit 3
Bit 2
Bit 1
Bit 0
Modem Signal Value Registers (MSVR)
Modem Signal Value Register (MSVR-RTS)
Modem Signal Value Register (MSVR-DTR)
Either of these registers is read to determine the current input levels on the input modem pins. Note
that the pin definitions for these signals is negative true while the register values are positive true.
Two registers are provided for control of the outputs — DTR and RTS. Writing to the MSVR-DTR
register affects only the DTR pin. Writing to the MSVR-RTS register affects only the RTS pin.
Bit 7
Bit 6
Bit 5
Bit 4
Bit 6
Bit 6
CD
CD
Intelligent Two-Channel LAN and WAN Communications Controller — CD2231
TxEn – Transmitter enabled status
When set, the transmitter is enabled.
When clear, the transmitter is disabled.
Reserved – must be ‘0’.
TFram – Transmit frame status
When set, a frame is being transmitted.
When clear, no frame is being transmitted.
TIdle – Transmitter idle status
When set, the transmitter output is idle.
When clear, the transmitter output is not idle.
Note that TFram and TIdle are mutually exclusive.
DSR – Current state of data set ready input
CD – Current state of carrier detect input
CTS – Current state of clear to send input
DTR option – written by MSVR-DTR register
0 = value of DTR bit is output on TXCOUT/DTR* pin
1 = Transmit clock is output on TXCOUT/DTR* pin
Bit 5
CTS
Bit 5
CTS
DTRop
DTRop
Bit 4
Bit 4
Bit 3
Bit 3
0
0
Bit 2
Bit 2
0
0
Motorola Hex Address: x’DE
Motorola Hex Address: x’DF
DTR
DTR
Bit 1
Bit 1
Intel Hex Address: x’DC
Intel Hex Address: x’DD
Bit 0
RTS
Bit 0
RTS
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