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odd behavior with serial PmmC for 96 and 128 oled

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  • odd behavior with serial PmmC for 96 and 128 oled

    Steve,
    Have not had a chance to check this out w/logic analyzer, but both the 96 G1 and 128 G1 seem to behaving differently from the manual. I loaded the latest serial Pmmc image on both and I can sync up with a U at a number of data rates. E correctly erases, V does give me version info but I need to send it twice and, B x x seems to correctly set background color but then the unit will not respond to any other command. I'm not sending any termination characters and the behavior seems repeatable at a number of baud rates. Any chance that the 96 G1 V1.0 manual is
    off? I'll try to verify the exact Rx/Tx traffic w/ a scope.

    Thanks,
    Chuck McP

  • #2


    The best way to isolate the problem is to use the Serial Commander utility to see if the problem is with the display (the PmmC in this case) or with the serial commands being sent by your host program. If you can control the display with the SC, then you need to look to your host program for the problem.

    Some of the serial commands take longer than others. That's why it's important that you wait for the ACK to be returned by the display before sending the next command. Serial commands are not buffered, so if you send the next serial command before the previous one has completed, data will be lost and the control stream will be out of sync. See the "Serial Timing:" section (page 10 of the uOLED-160-G1 User Manual for example).

    The most common reason for the display to stop accepting commands is the situation where either too many or too few bytes are passed to the display for a given command. If you pass 5 bytes of a command that requires 6, the display will wait for the 6th byte which may be the first byte of the next command which would cause the display to respond with a NAK.

    Good luck,

    Steve
    Any technology, sufficiently developed, is indistinguishable from magic. A.C. Clark(RIP)

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