mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 890

• Manufacturer Part Number: mpc823rg
• Description: Mpc823 Powerquicc Integrated Communications Processor For Portable Systems
• Manufacturer: Freescale Semiconductor, Inc

Communication Processor Module
16.12.3.3 SPI COMMANDS. The following transmit and receive commands are issued to
the CPM command register (CPCR).
• RRBPTR—The RX buffer descriptor pointer entry for each SPI channel points to the
• TBPTR—The TX buffer descriptor pointer entry for each SPI channel points to the next
• Other General Parameters—For normal operation, you do not need to access these
• INIT TX PARAMETERS—This command initializes all transmit parameters in the serial
• CLOSE RX BD—This command is used to force the SPI controller to close the current
• INIT RX PARAMETERS—This command initializes all the receive parameters in this
next buffer descriptor that the receiver transfers data to when it is idle or to the current
buffer descriptor during frame processing. After a reset or when the end of the buffer
descriptor table is reached, the communication processor module initializes this pointer
to the value programmed in the RBASE entry. Although in most applications you must
not write RBPTR, it can be modified when the receiver is disabled or when you are sure
that no receive buffer is currently in use.
buffer descriptor that the transmitter transfers data from when it is idle or to the current
buffer descriptor during frame transmission. After a reset or when the end of buffer
descriptor table is reached, the communication processor module initializes this pointer
to the value programmed in the TBASE entry. Although in most applications you must
not write TBPTR, it can be modified when the transmitter is disabled or when you are
sure that no transmit buffer is currently in use.
parameters. They are only listed here because they provide helpful information for
debugging purposes. Additional parameters are listed in Table 16-39. RPTR and TPTR
are updated by the SDMA channels to show the next address in the buffer to be
accessed. TCNT is a down-count value initialized with the DATA LENGTH field of the
TX buffer descriptor and decremented with every byte read by the SDMA channels. The
RCNT is a down-count value that is initialized with the MRBLR value and decremented
with every byte the SDMA channels write. The RSTATE, TSTATE, RTMP, TMP, and
reserved areas can only be used by the RISC microcontroller.
channel parameter RAM to their reset state and must only be issued when the
transmitter is disabled. The INIT TX AND RX PARAMS command can also be used to
reset the transmit and receive parameters.
RX buffer descriptor if it is currently being used and to use the next buffer descriptor for
any subsequently received data. If the SPI controller is not in the process of receiving
data, no action is taken by this command.
serial channel parameter RAM to their reset state and must only be issued when the
receiver is disabled. The INIT TX AND RX PARAMS command can also be used to
reset the receive and transmit parameters.
Note: To extract data from a partially full buffer, issue the CLOSE RX BD command.
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MPC823 REFERENCE MANUAL
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