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[on:]

Hi recently acquired a JN12864J lcd module from China how do i interface it with a atmega 328 also what libraries do i need ?


Thx

[Reply #1 on:]

Hi flak88,
To save people the hassle of hunting the web for details on the device a link to it would have been helpful.
A quick google finds thousands of references but most useful looking are http://arduino.cc/forum/index.php/topic,91732.msg688825.html#msg688825

[Reply #2 on:]

Good link. Crosscheck: If the display has a pin labeled with PSB, then it is a display with a st7920 controller.
You could use u8glib (http://code.google.com/p/u8glib/) with "U8GLIB_ST7920_128X64(...)"
Set a0 to U8G_PIN_NONE.

Oliver

[Reply #3 on:]

Sorry didnt post a direct link I bought the lcd from ebay it didn't have a datasheet in the description.

Had a look though the U8glib cant find the header that defines the pins to be used for this controller im using a atmega 328 btw.

Any ideas ?

[Reply #4 on:]

Hi

Google for ST7920.pdf. It will give you all required information:
Connect
PSB to GND
RS (chip select) to pin 2 of your Arduino
RW (serial data) to pin 3 of your Arduino
E (serial clock) to pin 4 of your Arduino

Then use:
U8GLIB_ST7920_128X64 u8g(4, 3, 2, U8G_PIN_NONE )

Of course you could use any other Arduino pins also.

Oliver

[Reply #5 on:]

Hi sorry for the long reply been busy.

Im having some problems trying to find the pin out in the g8lib im using a atmega 328

So far i have it connected like this:
PSB to GND
RS (chip select) to pin 2(D2 i assume ?
RW (serial data) to pin d3
E (serial clock) to pin d4

Where does the following go to on the atmega 328 ?
db0-db7
NC
RST
VOUT

Im using the following as a constructor in the hello world example from u8glib_arduino_v1.08 btw.
U8GLIB_ST7920_128X64 u8g(4, 3, 2, U8G_PIN_NONE )


Thanks

[Reply #6 on:]

NC: I assume this means "not connected"
RST: probably reset. U8glib can control this:
If you connect RST to pin 5, then use this:
U8GLIB_ST7920_128X64 u8g(4, 3, 2, U8G_PIN_NONE, 5 )
See the datasheet for details.
dbX pins are only used for parallel mode
VOUT is part of the external variable resistor.
Recently there was a thread about this here in the forum

Oliver

[Reply #7 on:]

about the variable resistor, see this thread: http://arduino.cc/forum/index.php/topic,133736.0.html

[Reply #8 on:]

It would seem the lcd module I have is slightly different to the example you posted.There is no V0 pin just VOUT.How do I wire up the contrast control pot with these pins ?

This is the current pinout of the lcd to atmega 328.
gnd->0v
vcc->+5v
0v->0v
jp2->(haven't gotta clue so left unconnected)
rs->pin 2
rw->pin3
e->pin4
db0-db7 (not connected)
psb->ov
nc->not connected
rst->pin5
vout->where does this go ?
a->470 ohm->+5v
k->0v


thx again

[Reply #9 on:]

There is no V0 pin just VOUT

Well, you did not provide much of information, but what i see from http://wenku.baidu.com/view/ebf9d797daef5ef7ba0d3c0b.html, i would say that there IS a "V0".

0v->0v

maybe this should be
V0->var. pot 

Oliver

[Reply #10 on:]

Ok

The problem is im not getting anything on the screen despite changing the contrast control.Im using the "hello world example" with the constructor you mentioned in your previous post.

gnd->0v
vcc->+5v
v0->wiper of pot
jp2->(haven't gotta clue so left unconnected)
rs->pin 2
rw->pin3
e->pin4
db0-db7 (not connected)
psb->ov
nc->not connected
rst->pin5
vout->one end of pot
a->470 ohm->+5v
k->0v

I didn't have any 10k pots so used a 20k pot instead.
contrast control pot is wired like the following:
wiper to pin3 on the lcd(v0)
one end of pot to gnd
other end to VOUT of lcd


Any ideas ?

[Reply #11 on:]

Try to connect "rst" to +5V, will this work?

Maybe you can send a picture of your setup.
Still, you have not posted a proper datasheet, but from the information I have, all looks fine.

Oliver

[Reply #12 on:]

It works now after connecting rst to +5v.
Thanks very much.