mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 887

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

16.12.3.2 SPI PARAMETER RAM MEMORY MAP. The SPI parameter RAM area begins
at the SPI base address and is used for the general SPI parameters. Notice that it is similar
to the SCCx general-purpose parameter RAM. You must initialize certain parameter RAM
values before the serial peripheral interface is enabled. The communication processor
module initilizes the other values. Once initialized, the parameter RAM values do not usually
need to be accessed by your software. They only need to be modified when there is no serial
peripheral interface activity in progress.
• RBASE and TBASE—The dual-port RAM starts receiving and transmitting data for the
NOTE:
RX and TX buffer descriptors in the RBASE and TBASE entries. They provide a great
deal of flexibility for partitioning buffer descriptors for a serial peripheral interface. You
must initialize these entries before enabling the corresponding channel. You must not
configure the SPI buffer descriptor tables to overlap with the tables of the USB, SMCx,
and SCCx or erratic operation will occur. RBASE and TBASE must contain a value that
is divisible by eight.
SPI Base + 1C
SPI Base + 00
SPI Base + 10
SPI Base + 12
SPI Base + 14
SPI Base + 18
SPI Base + 20
SPI Base + 22
SPI Base + 24
SPI Base+ 0C
SPI Base+ 02
SPI Base+ 04
SPI Base+ 05
SPI Base+ 06
SPI Base+ 08
ADDRESS
You are only responsible for initializing the items in bold.
SPI Base = (IMMR & 0xFFFF0000) + 0x3D80.
SCCx Ethernet parameter RAM space overlaps the SPI parameter RAM space. The address range
for SCCx space is 0x1000 through 0x1CA3. You need a microcode patch to run SPI and Ethernet
concurrently.
Table 16-39. SPI Parameter RAM Memory Map
Freescale Semiconductor, Inc.
RSTATE
TSTATE
MRBLR
RBASE
TBASE
RBPTR
For More Information On This Product,
TBPTR
NAME
RTMP
RFCR
TFCR
RPTR
RCNT
TCNT
TTMP
TPTR
MPC823 REFERENCE MANUAL
Go to: www.freescale.com
Half-word
Half-word
Half-word
Half-word
Half-word
Half-word
Half-word
WIDTH
Word
Word
Word
Word
Word
Word
Byte
Byte
RX Buffer Descriptor Base Address
TX Buffer Descriptor Base Address
Maximum Receive Buffer Length
RX Buffer Descriptor Pointer
TX Buffer Descriptor Pointer
Communication Processor Module
RX Internal Data Pointer
TX Internal Data Pointer
RX Internal Byte Count
TX Internal Byte Count
RX Function Code
TX Function Code
RX Internal State
TX Internal State
DESCRIPTION
RX Temp
TX Temp
16-435