Motorola PPC/PMC-8260/DS1, Reference Manual, Page: 86 / 150

Loading Application Software Firmware
4 - 22 PPC/PMC-8260/DS1
Reading and Writing
Only part of the address space of the PPC/PMC-8260/DS1 is directly accessible
from the PCI bus (see the “Resources Used by the Primary Booter” section on
page 4-15). The other parts of the address map (e.g. boot flash area) can be
accessed by using the read and write command sequence. Program your software
according to the following description
1)
:
1. Define I/O buffer in area available for this purpose (01C40000
16
-
02000000
16
)
This is accomplished by writing the offset of the selected I/O buffer relative to
the beginning of the memory window into the COFF field (in big endian data
format).
2. When accessing hardware devices with a specific port size it might be
necessary to set the CWID field to 0
3. Write source/destination address (in the PPC/PMC-8260/DS1 address
space) of read/write operation into CADR field
4. Write number of bytes to be transferred into CSIZ field
5. For write operations, store data to be written into I/O buffer
6. Start read or write operation by writing command “read” or “writ” into
SYNC field respectively
7. Wait for completion (see “Basic Command Programming Procedure” on
page 4-19 and “Return Codes” on page 4-19).
In case of a read operation, data is now visible in I/O buffer
1) Using the primary booter for reading and writing operations requires also a programming routinge for
starting the primary booter.