CD1865 Datasheet, PDF (105/150 Pages) Intel Corporation – Intelligent Eight-Channel Communications Controller

Intelligent Eight-Channel Communications Controller — CD1865
9.2.3.2
Modem Request Acknowledge Register\
Register Name:
Register Description: Modem Request Acknowledge Register
Default Value: 80
Access: Read only
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Modified Interrupt Vector provided on read
8-Bit Hex Address: $75
Intel Hex Address: $EA
Motorola Hex Address: $EB
Bit 1
Bit 0
9.2.3.3
Transmit Request Acknowledge Register
Register Name:
Register Description: Transmit Request Acknowledge Register
Default Value: 80
Access: Read only
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Modified Interrupt Vector provided on read
8-Bit Hex Address: $76
Intel Hex Address: $EC
Motorola Hex Address: $ED
Bit 1
Bit 0
9.2.3.4
Receive Request Acknowledge Register
Register Name:
Register Description: Receive Request Acknowledge Register
Default Value: 80
Access: Read only
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Modified Interrupt Vector provided on read
8-Bit Hex Address: $77
Intel Hex Address: $EE
Motorola Hex Address: $EF
Bit 1
Bit 0
The Service Request Acknowledge registers are read-only registers that return an appropriate
interrupt vector when read. Reading one of these registers has the effect of a service
acknowledgment cycle in the CD1865 (not necessarily the one addressed; it may be one further
down the daisy chain). The vector supplied on the data bus during the cycle is described under the
Global Service Vector register description. RegAckEn must be set for these registers to operate
properly.
Datasheet
105