Quote Originally Posted by Dave View Post
Wow, is that thing slowwwwwwww. 600uS. for just about any of the control instructions? I really think you need to check your command and data delay settings. If I was using it I would also operate it in 8 bit mode. Twice as fast..... I also suggest reading the busy flag because if you are not then you are probably sending it instructions while it is executing the last instruction.
If the command and data delay settings are wrong or the device is too slow, why does it work perfectly with displaying letters and numbers? In addition, I could put a for/next loop from 0 to 33 and the bargraph routine runs perfectly hours on end. More testing reveals this:

Range.... Number where the bargraph is not displayed correctly
64 .... 4
128 .... 8
256 .... 16
512 .... 34
1024 .... 66
2048 .... 132

This means something, just not sure what. The one common thing I can see is that when one box (three vertical "l"'s) fills up, the next time the bargraph routine attempts to write to the next box, it will fail. If I adjust the column from 0 to 1, it will now allow me to successfully write four boxes instead of one.