Communication Processor Module
16-416
MPC823 USER’S MANUAL
MOTOROLA
SMC
COMMUNICATION
16
PROCESSOR
MODULE
To use the SMC GCI channels properly, the time-slot assigner in the serial interface must
be configured to route the monitor and circuit interface channels to the serial management
for more details on how to program this configuration. The SMC in GCI mode is also referred
to as the SMC GCI controller.
16.11.8.0.1 SMC GCI Monitor Channel Transmission Process. The monitor channel 0
is used to exchange data with a layer 1 device (reading and writing internal registers and
transferring of the S and Q bits). Monitor channel 1 is used for programming and controlling
voice/data modules, such as CODECs. The core writes the data byte into the transmit (TX)
buffer descriptor. The serial management controller transmits the data on the monitor
channel and handles the A and E control bits according to the GCI monitor channel protocol.
You can issue the TIMEOUT command to solve deadlocks when errors in the A and E bit
occur on the data line.
16.11.8.0.2 SMC GCI Monitor Channel Reception Process. The serial management
controller receives data and handles the A and E control bits according to the GCI monitor
channel protocol. When the communication processor module stores a received data byte
in the SMC receive (RX) buffer descriptor, a maskable interrupt is generated. You can issue
the TRANSMIT ABORT REQUEST command and the MPC823 transmits an abort request
on the E bit.
16.11.8.1 HANDLING THE SMC CIRCUIT INTERFACE CHANNEL. The circuit interface
channel is used to control the layer 1 device. The layer 2 device in the TE sends commands
and receives indication to or from the upstream layer 1 device via circuit interface channel
0. In the SCIT configuration, circuit interface channel 1 is used to convey real-time status
information between the layer 2 device and nonlayer 1 peripheral devices (CODECs).
16.11.8.1.1 SMC GCI Circuit Interface Channel Transmission Process. The core
writes the data byte into the circuit interface TX buffer descriptor and the serial management
controller transmits the data continuously on the circuit interface channel to the physical
layer device.
16.11.8.1.2 SMC GCI Circuit Interface Channel Reception Process. The SMC receiver
continuously monitors the circuit interface channel and when it recognizes a change in the
data and this value is received in two successive frames, it is interpreted as valid data. This
is referred to as the double last-look method. The received data byte is stored by the
communication processor module in the circuit interface RX buffer descriptor and a
maskable interrupt is generated. If the serial management controller is configured to support
SCIT channel 1, the double last-look method is not used.