CD2401 Intel, CD2401 Datasheet - Page 123

• Manufacturer Part Number: CD2401
• Description: Multi-protocol Communications Controller
• Manufacturer: Intel

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 6
Bit 5
Bit 4
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 the control of the DTR* and RTS* output pins: a write to MSVR-
DTR only affects DTR*; a write to MSVR-RTS only affects RTS*.
Bit 7
Bit 6
Bit 6
CD
CD
Reserved – always returns ‘0’ when read.
Receive Special
When this bit is set, it indicates that the CD2401 is currently in a steady-state condi-
tion. Such conditions generate a receive special character interrupt.
Reserved – always returns ‘0’ when read.
Transmitter Enabled status
0 = transmitter disabled.
1 = transmitter enabled.
Reserved – always returns ‘0’ when read.
Transmit Special
When this bit is set, it indicates that the CD2401 is currently transmitting an ETC
command, as defined in COR2.
Reserved – always returns ‘0’ when read.
This bit reflects the current state of DSR*.
Bit 5
CTS
Bit 5
CTS
DTRop
DTRop
Bit 4
Bit 4
Multi-Protocol Communications Controller — CD2401
Bit 3
Bit 3
0
0
Bit 2
Bit 2
0
0
Motorola Hex Address: x’DE
Motorola Hex Address: x’DF
DTR
Bit 1
Bit 1
DTR
Intel Hex Address: x’DC
Intel Hex Address: x’DD
Bit 0
RTS
Bit 0
RTS
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