Motorola MPC823e Reference Manual page 466

Communication Processor Module
The RISC microcontroller commands consist of the following:
• INIT TX AND RX PARAMS—The initialize transmit and receive parameter command
initializes the transmit and receive parameters in the parameter RAM to the values that
they had when the communication processor module was last reset. This command is
especially useful when switching protocols on a serial channel.
• INIT RX PARAMETERS—The initialize receive parameters command initializes the
receive parameters of the serial channel.
• INIT TX PARAMETERS—The initialize transmit parameters command initializes the
transmit parameters of the serial channel.
• ENTER HUNT MODE—The enter hunt mode command causes the receiver to stop
receiving and start looking for a new frame. The exact operation of this command
depends on the protocol that is used.
• STOP TX—The stop transmission command stops transmitting from this channel as
soon as the transmit FIFO has been emptied. It must only be used when transmissions
need to be stopped immediately. Transmission continues when the RESTART TX
command is issued.
• GRACEFUL STOP TX—The graceful stop transmission command stops transmitting
from this channel as soon as the current frame has been fully transmitted from the
transmit FIFO. Transmission continues when the RESTART TX command is issued
and the R bit is set in the next transmit buffer descriptor.
• RESTART TX—Once the STOP TX command has been issued, the restart
transmission command is used to start transmitting again at the current buffer
descriptor.
• CLOSE RX BD—The close receive buffer descriptor command causes the receiver to
close the current receive buffer descriptor, which makes the receive buffer available for
you to manipulate. The next available buffer descriptor is used to continue reception.
You can use this command to access the data buffer and you won't have to wait until a
serial communication controller fills it.
• INIT IDMA—The initialize IDMA command initializes the IDMA internal state to the
value it had at system reset. It is only required when the IDMA autobuffer or buffer
chaining modes are used.
• ARM IDMA—The arm IDMA command causes the IDMA to open the next buffer
descriptor in the table. It can be used to reduce the latency of servicing the first IDMA
request. Single buffer burst fly-by mode is only available for IDMA1.
• SET TIMER—The set timer command is used to activate, deactivate, or reconfigure the
16 timers of the RISC timer table.
• SET GROUP ADDRESS—The set group address command sets a hash table bit for
the Ethernet logical group address recognition function.
• GCI ABORT REQUEST—The GCI abort request command causes the MPC823e
receiver to send an abort request on the A bit of the GCI bus.
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