tomcody Posted May 10, 2011 Report Share Posted May 10, 2011 Hi everybody I finished my mbfm + built-in 4-channel stereo mixer + tone control. I built it around a heathkit ET-3200 case. The mixer has balance, volume, phone amp and RCA connectors. I used a dvd player power supply (+5/+12/-12) and works fine. Here some pictures. But I have a problem: with a 18F452 the LCD works fine, but when I use a 4685 it gets stuck after pressing/rotating a little bit here and there (but the rest still working, it plays notes and I can change parameters ...). I looked around and realize that 4865 works in 4-bit mode with the LCD, but still the problem after fixed that. I thought in a corrupted midi transfer but the 452 works fine. What can be the problem? Thank in advance for your comments. Quote Link to comment Share on other sites More sharing options...
lucem Posted May 10, 2011 Report Share Posted May 10, 2011 Did you wire up four or eight data lines to the lcd? In 4 bit mode, if you wire up the additional lines D4..D7, this can introduce an error condition. So, if you did wire those up, remove them and leave them open. Quote Link to comment Share on other sites More sharing options...
tomcody Posted May 10, 2011 Author Report Share Posted May 10, 2011 first I wired up the 8, then only 4 and D0-D3 from the LCD to ground and D0-03 from CORE open. The strange thing is it doesn't get stuck when I move the data dial, but when I use the selection matrix or the v-pots it gets stuck after 3 seconds ... I don't understand why, please any help? Thank you for your reply. Quote Link to comment Share on other sites More sharing options...
tomcody Posted May 11, 2011 Author Report Share Posted May 11, 2011 here some photos: as you can see just a part of the LCD get refreshed, then get stuck and I have to power off-on. Quote Link to comment Share on other sites More sharing options...
tomcody Posted May 11, 2011 Author Report Share Posted May 11, 2011 sorry too big photos: Thank you in advance for any comment. Quote Link to comment Share on other sites More sharing options...
Janis1279 Posted May 11, 2011 Report Share Posted May 11, 2011 first I wired up the 8, then only 4 and D0-D3 from the LCD to ground and D0-03 from CORE open. The strange thing is it doesn't get stuck when I move the data dial, but when I use the selection matrix or the v-pots it gets stuck after 3 seconds ... I don't understand why, please any help? Thank you for your reply. Wiring Diagram: mbhp_lcd_mios8.pdf If a PIC18F4685 is used in the project (-> MIDIbox SID V2), the LCD is accessed in 4bit mode. Accordingly, the data pins D0/D1/D2 and D3 should be left open at core and LCD side (don't connect them to ground!) - see mbhp_lcd_4bit_mios8.pdf Quote Link to comment Share on other sites More sharing options...
tomcody Posted May 11, 2011 Author Report Share Posted May 11, 2011 Thank you for your reply. Wiring Diagram: mbhp_lcd_mios8.pdf If a PIC18F4685 is used in the project (-> MIDIbox SID V2), the LCD is accessed in 4bit mode. Accordingly, the data pins D0/D1/D2 and D3 should be left open at core and LCD side (don't connect them to ground!) - see mbhp_lcd_4bit_mios8.pdf Yes I set the connectios like that but the problem persist. Then looking in the wiki I found this: ;; using the 4-bit interface: ;; -> connect MBHP_CORE:J15:D7-D4 of the core module to D7-D4 of the LCD ;; -> left MBHP_CORE:J15:D3-D0 of the core module open! ;; -> tie D3-D0 of the LCD to ground So I tried it (D3-D0 of the LCD to ground and D3-D0 of CORE open), but again the problem persist, I don't know what else to try. Quote Link to comment Share on other sites More sharing options...
tomcody Posted May 12, 2011 Author Report Share Posted May 12, 2011 I think I found the problem. I'm using a dvd player switching power supply and its +5 Volts varies between 5.25 and 5.4 Volts. I tried with 5.0 volts coming from an adjustable power supply and the LCD works fine, never got stuck. May be is the PIC or the LCD that have problems with voltages around to its limit (5.5 Volts). Well I hope my experience can help somebody. Quote Link to comment Share on other sites More sharing options...
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