Strange 56F807 SPI Control Register (SPSCR) Behavior

Started by Litinas, Terry October 22, 2003
Hi All,

I am working with the 56F807, CodeWarrior 5.1.1, and SDK 3.0 and have
noticed that when writing to the COPCTL register (address $1330), the data
in the SPSCR (address $1320) changes. I am monitoring the registers in a
memory window (Swap Endian option set) as I step through the following code:

copInitialize (COP_SETUP, COP_TIMEOUT);
P:000023BC: 86F413325555 movei #21845,X:0x1332
P:000023BF: 86F41332AAAA movei #-21846,X:0x1332
P:000023C2: 86F413310031 movei #49,X:0x1331

**********************SPSCR = 0x1492 before writing to COPCTL (address
P:000023C5: 86F41330000F movei #15,X:0x1330
**********************SPSCR = 0x0214 after writing to COPCTL (address $1330)

Can't figure out how a write to the COPCTL reg affects the data in the SPSCR
reg. It is very repeatable. I have killed and restarted the debugger, cycled
power on the target hardware, and re-downloaded the executable to the 807. I
don't see anything in the 807 errata to explain it. I'm wondering if anyone
else has seen anything like this???

Thanks in advance,

Terry Litinas
Project Engineer
ITW Balance Engineering
1731 Thorncroft
Troy, Mi. 48084

Ph: (248)643-2876
Fx: (248)643-2888