mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 920

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

Communication Processor Module
DATA LENGTH
This field represents the number of octets that the communication processor module writes
into this buffer descriptor data buffer. The communication processor module writes it once
the buffer descriptor closes. The I
placed into the associated data buffer. The actual amount of memory allocated for this buffer
must be greater than or equal to the MRBLR entry.
RX DATA BUFFER POINTER
This field always points to the first location of the associated data buffer. It must be even and
can reside in internal or external memory. The I
received data is placed into the associated data buffer.
16.13.7.3 I
sent to the communication processor module by arranging it in buffers referenced by the
transmit (TX) buffer descriptor ring. The first word of the TX buffer descriptor contains status
and control bits. You must prepare the following bits before transmitting data.
R—Ready
Bits 1 and 6–12—Reserved
These bits are reserved and must be set to 0.
OFFSET + 0
OFFSET + 2
OFFSET + 4
OFFSET + 6
NOTE:
0 = The data buffer associated with this buffer descriptor is not ready for transmission.
1 = The data buffer, which you prepare for transmission, is not transmitted yet or is
You are only responsible for initializing the items in bold.
You are free to manipulate this buffer descriptor or its associated data buffer. The
communication processor module clears this bit after the buffer is transmitted or
after an error occurs.
currently being transmitted. You cannot write any fields of this buffer descriptor
once this bit is set.
R
0
2
C TRANSMIT BUFFER DESCRIPTOR. Data to be transmitted with the I
Note: The communication processor module sets all the status bits in this buffer
RES
1
W
descriptor, but you must clear them before submitting the buffer descriptor to the
communication processor module.
2
Freescale Semiconductor, Inc.
For More Information On This Product,
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I
MPC823 REFERENCE MANUAL
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L
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Go to: www.freescale.com
C controller writes these bits after the received data is
S
5
TX DATA BUFFER POINTER
6
DATA LENGTH
7
2
C controller writes these bits after the
8
RESERVED
9
10
11
12
NAK
13
MOTOROLA
UN
14
2
C is
CL
15