tomcody

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.

Thank you for your reply. 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.

sorry too big photos: Thank you in advance for any comment.

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.

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.

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.

Thanks for your reply Imp, fortunately I have a 18f452 and did the connection test with it and all OK ... :thumbsup:. Then I loaded setup_pic18f452_mbfm_tk.hex and the LCD showed me the mbfm menu ... :thumbsup:. Then I loaded the 1kHz test sound and it sounded in all the channels ... :thumbsup:. :laugh: :laugh: :laugh: :laugh: !!!! I don't understand why the LCD doesn't showed anything with the 18f4685 ... I used the latest .hex files: bootloader_v1_2b_pic18f4685.hex mios_v1_9g_pic18f4685.hex setup_pic18f4685_mbfm_tk.hex Maybe because of using the minimal requirements? Well I don't use ferric chloride, instead I use nitric acid and takes less than a minute and goes a long way ... in fact I have to water down a lot this thing or the PCB will end with no copper and all the toner floating in 3 seconds :rofl: Well I think for the momment is solve my problem but the 18f4685 thing. Thank you again for taking the time. Tom.

Hello, I'm making the MIDIBox FM and at this momment my system is like the minimal: CORE with PIC18f4685 + MBHP_OPL3 + LCD + bankstick. In this I posted that some pin of the YAC512 was unconnected to ground. Finally I finnished the MBHP_OPL3 without ground plane, so the ground of 5+ was unconnected to the ground of +12-12. When I tested the module for the first time the OPL3 chip got a little warm, I did the connection test (mbfm_interconnection_test_v2) and the D0, D1, D2 & D3 pins always reads 5V. The remaining pins works OK (the LCD worked OK too). After this I loaded setup_pic18f4685_mbfm_tk.hex with all my system interconnected hoping the LCD will shows me something but nothing happened (just the upper LCD line in black). Then I loaded the 1kHz triangle test and no sound :sad:. After 4 or 5 times the OPL3 chip doesn't got warm anymore :huh:. Then I realized that the oscillator's GND pin was connected to the +12-12's ground and not to the +5's ground so the oscillator never got power and the OPL3 chip never got the clock signal, now it's fixed. I did triple check both circuits. summarizing: CORE are working OK except D0, D1, D2 & D3 pins (I think). LCD working OK. MBHP_OPL3 PCB OK and all components correctly mounted, green led lighting. CORE & MBHP_OPL3 connection OK. Not soldered, but through ribbon cable connection (see pic). I'm afraid my attempt to save toner was the error (no ground plane). Could this damage the OPL3 chip :bye:?. Maybe the clock pin was floating because of that and that's why got warm I dunno... Thank you in advance for any reply.

I do understand it's upside down, in my case I have to connect the pin 2 to groud because I'm not making the PCB with ground plane (toner saving :wink:) and that's the only commponent (appears to be) is not physically connected to ground line. Thanks for your replies.

Hello everybody I realized that in the IC2 (upper YAC512) the VSS pin is not physically connected, however when using ratsnest appears connected. I'm not a specialist but how can IC2 work without a ground? Thank you in advance :smile:

Yesterday I've received my opl3 chipset thank you! :smile:

wow monokinetic! thanks that's a good page, I will try that circuit and follow the Janis1279's indications and post the result, if doesn't work I will follow the nILS's indications and hope for the good will of an midiboxer :D . Thank you everybody. TomCody

Hello everybody, I'm starting gathering the part to make an midibox fm and I realized the difference between a crystal and oscillator ... but too late :tongue: 'cuase I bought a bunch of crystal from ebay. I know there are a lot of webshops but the shipping to my country are very expensive compared to ebay. So I've found this page looking for a solution: http://www.gaby.de/z80/uexosc.htm I saw the scope pictures about the 74LS00 circuit and looks like a nice TTL pulse at the output :thumbsup: , so this may work, but the guy doesn't specify the max frec. this cicuit will work (the circuit uses a 4 MHz crystal), maybe a 74HC00, I don't know. The bad thing is if someone choose this solution needs to make a circuit apart for this or to know how to use the eagle to edit the schematic. Have anyone use something like this? What do you think? Thanks you. TomCody.