| ??? 04/23/07 05:04 Modified: 04/23/07 05:05 Read: times |
#137780 - looks like experimenting again ... Responding to: ???'s previous message |
Mike Stegmaier said:
What I would recommend is to increase the delay, especially if you have a high speed crystal. What do you know about the timing of this code? Do you know what MCU and crystal the O/P is using? If you don't, how can you make such a recommendation? Also, I would suggest that the data is loaded BEFORE the LCD enable sequence commences. I discovered myself that when enable rises from low to high, data is written. Have you consulted the HD44780 datasheet to verify this? I don't believe this is correct. It's true, however, that the E signal should be the last one to be activated, whereupon it should be timed out and deactivated before anything else is changed. Since you have the first half of the program working, the only piece of hardware you should be changing if any is your external code ROM (if any) or your crystal. Dropping your crystal speed can help. Until you know what the crystal speed and MCU type is, you can't rationally recommend such things. The minimal duration for E is nominally 400 ns. On most MCU's it's not necessary to do anything other than set E followed immediately by clr E. Also, try programming the code on a new ROM. How, exactly, and why, is that supposed to make any difference? RE |
