SounDuke Posted March 9, 2005 Report Share Posted March 9, 2005 I connected my ATM1602b (see http://www.hebeiltd.com.cn/lcm.datasheet/ATM1602B.doc) and I tried to connect power to the core to see if it worked. I didn't put the pic on the core yet, is it necessary to test the LCD? I thought at least the backlight would turn on by simply supplying the anode and the cathode of the LCD Quote Link to comment Share on other sites More sharing options...
SounDuke Posted March 9, 2005 Author Report Share Posted March 9, 2005 Or I need to plug the PIC on to activate the backlight too? All of the connections and the voltages are OK, except for + and - of the backlight. In the datasheet recommended voltage is 4.2V in anode and 0V in cathode , but due to the voltage regulator in the core the voltage supplied is 5V. Quote Link to comment Share on other sites More sharing options...
moebius Posted March 9, 2005 Report Share Posted March 9, 2005 Hi,No need to plug PIC in the place to get backlight working - just watch that you connect it the right way. Rotate P1 (or "Luminance") trimmer on core board to adjust backlight brightness.Bye, Moebius Quote Link to comment Share on other sites More sharing options...
SounDuke Posted March 9, 2005 Author Report Share Posted March 9, 2005 I tried to rotate, but nothing happened. I thought the problem was the trimm, so I checked resistance between the pin of J15 which connects to the positive pole of the LCD backlight and the trimm.0 in the two pins of the trimm, and the value selected rotating the trimm on the 3rd pin.Measuring between the pin of J15 which is to connect to the - pole of the lcd backlight, I found 10k on the 2 pins of the trimm and 13,5 k on the 3rd pin!Is it possible that the problem is the trimm? Maybe I harmed it during soldering Quote Link to comment Share on other sites More sharing options...
moebius Posted March 9, 2005 Report Share Posted March 9, 2005 "Trace the tracks, Luke" - Core Schematics and Boards don't match around "Luminance" trimmer, which doesn't effect the normal functionality. (and the schematics are "correct" from the EE point of view as if trimmer wiper should lose it's contact to track, it should reset to maximum resistance.. yakety-yak)So, your measurements are OK - If you have moved the trimmer, you would have seen resistance go from approx. 10k <-> 20k.What if you tried powering core with no PIC or LCD connected and measured voltage between J16 B+ and B- pins and then moved the trimmer and measured again?Bye, Moebius Quote Link to comment Share on other sites More sharing options...
SounDuke Posted March 9, 2005 Author Report Share Posted March 9, 2005 Look at the datasheet I provided aboveI supplied the two poles of the LCD directly without passing through the core to see if the problem was related to the LCD. It lighted.I suppose that the LCD isn't useable for midibox, being an extended temperature range LCD it requires a negative voltage (4.2 anode or 5V max and 0V cathode) which the core output of J15 cannot supply (maybe). I'll try searching a new LCD Quote Link to comment Share on other sites More sharing options...
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