
Programmable Four-Channel Communications Controller
—
CD2481
Datasheet
157
Bit 6
RxFloff
–
Receive flow off status
When set, XOFF has been transmitted as commanded in the STCR. RxFloff indi-
cates that the remote station has been requested to stop transmission. RxFloff
remains set until the host issues an STCR command to send an XON, or when the
receiver is enabled or disabled, or the channel is reset.
When clear, the remote station is not requested to stop transmission. RxFloff remains
set until the host issues an STCR command to send an XON.
Bit 5
RFram
–
Receive frame status
When set, a frame is being received.
When clear, no frame is being received.
Bit 4
RIdle
–
Receiver idle status
When set, the receiver input is idle.
When clear, the receiver input is not idle.
Notice that RFram and RIdle are mutually exclusive.
Bit 3
TxEn
–
Transmitter enabled status
When set, the transmitter is enabled.
When clear, the transmitter is disabled.
Bit 2
TxFloff
–
Transmit flow off status
This bit has no meaning unless TxIBE in COR2 is set.
When set, an XOFF has been received, and the transmitter has stopped sending data.
When clear, the transmitter is able to transmit if there are characters to send.
Bit 1
TFram
–
Transmit frame status
When set, a frame is being transmitted.
When clear, no frame is being transmitted.
Bit 0
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.
CSR
–
SLIP/MNP4 Mode
Bit 7
RxEn
–
Receiver enabled status
When set, the receiver is enabled.
When clear, the receiver is disabled.
Bit 6
Reserved
–
returns
‘
0
’
when read.
Register Name: CSR
Register Description: Channel Status Register
Default Value: x
’
00
Access: Byte Read/Write
Intel Hex Address: x
’
19
Motorola Hex Address: x
’
1A
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RxEn
0
RxFrame
Ridle
TxEn
0
TxFrame
Tidle