Upgraded to a bigger LCD, not working anymore

Mesmer · Post by **Mesmer** » July 7th, 2009, 8:23 pm

Hello, first of all i'd like to thank the people involved with developing this software.

The first LCD i used was a 2x16 sanyo DM1622 with a genuine HD 44780 driver, managed to get it to work just fine. Shortly after i bought a bigger 4x20 with B/L lcd ( the sanyo didn't have one) and i can't get it to work. As far as i know the new one uses a clone driver, but it has the same pins/functions. The only change i've made in smartie is switch to 4x20 in the display select, using the same HD dll.

In both cases i've used the wiring shown on this website
http://www.icehw.net/article.php?id=104

I've noticed that GND isn't wired to the paralel port here, tho it worked fine for the smaller LCD. After hooking up the new LCD it showed some characters from my old smartie screens, then just froze. After resetting it just displays 2 rows of "full" characters all the time.

The bigger LCD has this datasheet http://home.comet.bg/datasheets/LCD/AC-204B.pdf and i think i've checked the wiring about 5 times now with my multimeter.

AJ256 · Post by **AJ256** » July 8th, 2009, 8:16 am

I'm not sure that LCD will work with smartie.

It uses 1 enable pin for 4 display lines, whereas a standard HD44780 compat controller has 2 enable pins for 4 lines (someone correct me if I'm wrong).

Post by **mattcro** » July 8th, 2009, 10:24 am

4x20 LCDs only have 1 Enable pin (4x40 LCDs have 2 enable pins), and the SED1278 controller on Mesmer's 4x20 is supposed to be HD44780 compatible, so it should work with the standard wiring. There are better (official Smartie) schematics at http://lcdsmartie.sourceforge.net/circuits.htm so double-check against them.

You should really have a connection from the LCD ground to the parallel port ground (pins 18-25). You definitely need this if you are using an external power supply, but ICEHardware have got away without it because they use the PC's own power supply so the grounds are connected via the power supply.

Mesmer · Post by **Mesmer** » July 8th, 2009, 11:21 am

I am also using the PC power supply. Atm i am remaking the wire, i wanted to add some molex connectors to the lcd anyway. Now i'll follow the layout on the smartie homepage. Btw, is there any software that would allow me to send data to the paralel port, or view data sent by the PC (i.e. see what smartie is sending? )

I see that port95nt has some interface, "VBportIO" and "C++portIO"
How can i see the data sent on paralel pins 1 to 9?

Mesmer · Post by **Mesmer** » July 8th, 2009, 1:24 pm

Oh well, i have redone the wiring as i said i would, basically used the schematic on the smartie site minus the pots and the GND for the parallel connector (using PC power supply) and it works!

Can't believe it was the wiring, i've checked it multiple times with the multimeter link function.

AJ256 · Post by **AJ256** » July 8th, 2009, 7:20 pm

Ahh yes, sorry about the false informations, I didn't realise that 4x20s had only 1 enable pin