CD2481 Datasheet, PDF (155/222 Pages) Intel Corporation – Programmable Four-Channel Communications Controller

Programmable Four-Channel Communications Controller — CD2481
9.4.3.1
CSR -–Asynchronous Mode
Register Name: CSR
Register Description: Channel Status Register
Default Value: x’00
Access: Byte Read/Write
Bit 7
Bit 6
Bit 5
Bit 4
RxEn
RxFloff
RxFlon
0
Bit 3
TxEn
Intel Hex Address: x’19
Motorola Hex Address: x’1A
Bit 2
TxFloff
Bit 1
TxFlon
Bit 0
0
If the host determines that a flow control state is inappropriate, it can be cleared by enabling or
disabling the transmitter or receiver by CCR command.
Bit 7
Receiver enable
0 = Receiver is disabled
1 = Receiver is enabled
Bit 6
Receive flow off
0 = Normal
1 = The CD2481 has requested the remote to stop transmission (Send XOFF com-
mand has been given to the channel). This bit is reset when the CD2481 has
requested the remote to restart transmission, or when the receiver is enabled or dis-
abled, or the channel is reset.
Bit 5
Receive flow on
0 = Normal
1 = The CD2481 has requested the remote to restart character transmission (Send
XON command has been given to the channel). This bit is reset when the next (non-
flow control) character is received, or when the receiver is enabled or disabled, or
the channel is reset.
Bit 4
Reserved – returns ‘0’ when read.
Bit 3
Transmitter enable
0 = Transmitter is disabled
1 = Transmitter is enabled
Bit 2
Transmit flow off
0 = Normal
1 = The CD2481 has been requested by the remote to stop transmission. This bit is
reset when the CD2481 receives a request to resume transmission, or when the trans-
mitter is enabled or disabled, or the channel is reset.
Bit 1
Transmit flow on
0 = Normal
1 = The CD2481 has been requested by the remote to resume transmission. This bit
is reset once character transmission is resumed, or when the transmitter is enabled or
disabled, or the channel is reset.
Bit 0
Reserved – returns ‘0’ when read.
Datasheet
155