128x64 Parallel/Serial GLCD using ST7920 Controller - Sketch. Arrising from the different codes (serial. The Code: I used U8GLIB_ST7920_128X64.

Dear All, Can anyone please provide links for: 1. Complete sketch (from start to end) using ST7920 Controller for this Parallel/serial selectable GLCD (128x64) according to this GLCD's specific pinouts (see below) and 2. Assemblies Of God Nigeria Sunday School Manual on this page. The full Pinout for the Mega2560 Board connecting this GLCD; There are numerous sketches and very different 128x64 GCLD's Controllers out there BUT none seem to be for the above combination.

Or the information that is available is only discernable by one who is fully conversant with the programming languages. I have located the Datasheet, (DS) for the ST7920 controller - and readers looking for this information need to be aware there are various publication dates for this specific DS ranging from Oct 2002 to Aug 2008 and possibly later as well, and they can be substantially different or don't include the same pin assignments - which adds to both the difficulty in trying to nut this out yourself and creates even more confusion since almost all these 'other' GLCD's use two pins, CS1 & CS2 instead of a single pin, E? The correct pinout for my 128x64 GLCD which carries the only identifying feature of J12864 followed by two chinese characters is: Pin 1 - GND; Pin 2 - Vcc; Pin 3 - Vo; Pin 4 - RS; Pin 5 - R/W; Pin 6 - E; Pin 7 to Pin 14 - DB0 to DB7; Pin 15 - PSB (Parallel-H/serial-L select); Pin 16 - NC; Pin - 17 RST; Pin 18 - Vout; (from internal voltage doubler); BLA (Backlight annode); Pin 20 - BLK (Cathode). I hope someone can please put me out of my misery and point me in the right direction. I have, I believe thoroughly chceked( Mdk Arm 4.13a & Rl-arm 4.12 & Hlp. ??) both the Arduino and Adafruit sites but to no avail???

Hi Oliver, Thank you again for your quick reply. I am however a tad confused with some of what you have said, eg,; '. Connect E, RW, RS and RST with some GPIO ports of your board.' I understand the GPIO [Serial??] ports on the Mega2560 to be TX/RX pairs - pins 14 to 19? Are you suggesting that 'E' should connect to (say) TX3 (Pin 14); 'RW' connects to RX3 (Pin 15); 'RS' to TX2 (Pin 16); 'RST' to RX2 (Pin 17) I also presume that pins DB0 - DB7 on the GLCD will be connected to Mega2560 digital pins (say) 21 - 27??? I have looked at the U8glib and have located the appropriate line to 'uncomment' but need the above to be clarified first. There is also much confusion with a great many of the available sketches (not necessarily the ST7920 controller) on whether a resistor should also be put in series with BLA (220 ohm is suggested when using +5V) in addition to including the variable pot (10K??) to control contrast on Vo?

Appreciate your clarification please. Also is there a completed sketch available for both the serial and parallel operation of the same GLCD - if so this would go a long way to seeing what the actual code differences are for both serial and parallel code - and therfore this too would help eliminate confusion arrising from the different codes (serial/parallel) for these different modes of driving the same GLCD?

Regards, Ian. Kwp 2000 Plus Manual on this page. Hi GPIO = means 'General Purpose Input/Output'. You can use any four pins of your board.

It does not matter which you use. The good thing about serial mode is, that you do not need to connect DB0 to DB7. See my picture. I have only connected four lines (white wire) with my Arduino board.

Uncommenting a line in u8glib might not need to be enough.You might need to modify the arguments (=pin numbers) of the constructor call. BLA and BLK usually is the power supply for the BackLight LED. It will require an additional (fixed) resistor. 10K should be fine for the variable pot. Without the datasheet of your display it is difficult to say something reliable, but in general the wiper should be connected to v0.

One end to GND and the other end to some negative voltage. Thanks once again Oliver, Re GPIO's - do you mean you can use 4 x digital or 4 x analog pins for these connections or any combination of either, and not the use the TX/RX pins at all? Re Uncommenting the U8glib line might not be enough - I was wondering about this as I could not see anywhere in U8glib code where 'E, RW, RS and RST' were being defined with respect to which pin numbers were connected to Mega2560 pins??? Do you have an example code line for this specific process of 'telling the code which Mega2560 pins are being used'? I could not see any other similar example in any of the various U8glib code statements that I could see here, either? By the way, I uncommented the code which still only showed the parameters 'E, RW, RS and RST' as these alpha characters but had not substituted any Mega2560 pin numbers and then compiled the code - which compiled OK showing no errors!