mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 891

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

16.12.3.4 SPI BUFFER DESCRIPTOR RING. The data associated with the serial
peripheral interface is stored in buffers, which are referenced by buffer descriptors
organized in a buffer descriptor ring located in the dual-port RAM. This ring has the same
basic configuration as the SCCx, SMCx, USB, and I
The buffer descriptor ring forms a circular queue that helps you organize the buffers you
want to transmit or receive. Using the buffer descriptors, the communication processor
module confirms reception and transmission or indicates error conditions so that the
processor knows the buffers have been serviced. The actual buffers can reside in either
external or internal memory and the data buffers can reside in the parameter area of another
unused controller if it is not enabled.
POINTER TO SPI
POINTER TO SPI
DUAL-PORT RAM
TX DATA BUFFER
RX RING
TX RING
Freescale Semiconductor, Inc.
For More Information On This Product,
Figure 16-121. SPI Memory Format
MPC823 REFERENCE MANUAL
Go to: www.freescale.com
FRAME STATUS
FRAME STATUS
DATA POINTER
DATA POINTER
DATA LENGTH
DATA LENGTH
TX BD RING
RX BD RING
2
C controllers.
Communication Processor Module
EXTERNAL MEMORY
TX DATA BUFFER
RX DATA BUFFER
16-439