F28027 Ramp Generator Shadow Register not writable

Daniel,

Can you check to see if the writes are successful if you modify the address directly through CCS Memory Browser?  Also, can you confirm that the associated COMPxENCLK bit is set?

-Tommy

Hi Tommy,

the COMPxENCLK bit is set also, like in the comparator description, COMPDACEN and ADCBGPWD are set to 1. The Comparator is working fine and Results are written in the DACVAL regster too. Only the two Registers RAMPMAXREF_SHDW and RAMPDECVAL_SHDW are not writable, on both comparators! In the Memory Browser, it´s also not possible. It´s very strange.

Best Regards

Daniel

Daniel,

Let's try another sanity check.  I was able to do the following successfully on my F28027 device and I would like to see if you can duplicate it:

1. Launch target configuration for F28027 in CCSv5
2. In the Debug view, remove the GEL file from memory (Tools->GEL Files; Right-click on GEL file & remove)
3. Connect to the device
4. Perform a CPU reset
5. Manually perform these write operations through the memory view:

• 0x7020 |= 0x0003; (Default value should be 0x2700)
• 0x640A  = 0xFFFF; (Default value should be 0x0000)
• 0x640E  = 0xFFFF; (Default value should be 0x0000)

Hi Tommy,

I tried it , and it did work. I also tried again to write in the memory browser while debugging (with the gel file included), and it did work too. Perhaps, I made somthing the last time wrong, at writing in the memory browser (Sorry for this, I know, its not difficult to use the memory browser). But the allocation still doesn´t work.

Best regards,

Daniel

Daniel,

At least this tells us that your device registers are ok, but there is something wrong with the software writes.  I would recommend single-stepping through the code that writes to those registers while keeping an eye on the memory browser.  Either the clock is being disabled somewhere or the software is trying to write to the wrong addresses.

-Tommy