Motorola MC68302 User Manual page 114

The GCI signals are as follows:
L1CLK
L1TXD
L1RXD
L 1SY1
L1GR
SDS1
SDS2
GCIDCL
GCI clock; input to the IMP.
GCI transmit data; open drain output.
GCI receive data; input to the IMP.
GCI SYNC signal; input to the IMP.
Grant permission to transmit on the D channel; input to the
IMP.
Serial data strobe 1
Serial data strobe 2
GCI interface data clock
The GCI bus has five channels:
B1
64-kbps Bearer Channel
B2 64-kbps Bearer Channel
M
64-kbps Monitor Channel
D
16-kbps Signaling Channel
C!I
In addition to the 144-kbps ISDN 2B
+
D channels, GCI provides two channels
for maintenance and control functions.
The monitor channel is used to transfer data between layer-1 devices and
the control unit (i.e., the M68000 core). The command/indication channel is
used to control activation/deactivation procedures or for the switching of test
loops by the control unit.
MOTOROLA
MC68302 USER'S MANUAL 4-11