ST7565 WITH PIC16F877A

blackmort · Joined: 19 May 2013 Posts: 7

Hello,

I try use a graphic LCD ( displaytech 64128N ( https://www.displaytech-us.com/sites/default/files/display-data-sheet/64128N%20series.pdf)) with PIC16F877A. I see this post (http://www.ccsinfo.com/forum/viewtopic.php?p=154055) but I do not arrive has to show of the text on the screen.

LCD PIC

RD | C3
A0 | C4
WR | C5
CS1 | C6
LCD_RESET | C7

LCD :

PIN1 GND
PIN2 +3V
PIN3 +3V
PIN17 +3V
PIN18 GND

http://img4.hostingpics.net/pics/831043CIMG0953.jpg

Sorry for my bad english.

dyeatman · Joined: 06 Sep 2003 Posts: 1941 Location: Norman, OK

What version of CCS compiler are you using?

If you have directly connected the PIC 5V outputs to the 3.3V display
you have quite possibly damaged the display. You MUST have some
type of level conversion between them.
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blackmort · Joined: 19 May 2013 Posts: 7

I use 3V for display and 5V (pickit usb ) for PIC16f877a

dyeatman · Joined: 06 Sep 2003 Posts: 1941 Location: Norman, OK

That much I understand.
You not answer my question, what version of CCS compiler are you using?

Also, are the outputs of the PIC connected directly to the display inputs?
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blackmort · Joined: 19 May 2013 Posts: 7

Yes display is directly connected to the pic and i use ccs 4.084

dyeatman · Joined: 06 Sep 2003 Posts: 1941 Location: Norman, OK

OK, I repeat,

blackmort · Joined: 19 May 2013 Posts: 7

https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-prn2/970279_10200570854068084_935456307_n.jpg
I use for R1 1 resistor 10K and for R2 two resistor 10k in serie .
I have 3.2V in my display pin . It's good ?

I don't can use my pic in 3V ( 4V-5,5V)
http://microcontrollershop.com/product_info.php?products_id=992

dyeatman · Joined: 06 Sep 2003 Posts: 1941 Location: Norman, OK

The voltage divider will do for the signals going to the display.

Read the Microchip datasheet. If you can run at 10MHZ or less the 877A
WILL work at 3.3V Page 174.

How/where are your data output pins connected?
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blackmort · Joined: 19 May 2013 Posts: 7

Thank you I did not know but with resistor he will work?
I use port D for keypad row ( rd4 to rd7 ) I does not know how to connect inputs of data with the code to find this above.
http://www.ccsinfo.com/forum/viewtopic.php?p=154055

dyeatman · Joined: 06 Sep 2003 Posts: 1941 Location: Norman, OK

The resistor dividers you described should be just fine for the outputs.
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blackmort · Joined: 19 May 2013 Posts: 7

#Define RD PIN_C3
#Define A0 PIN_C4
#Define WR PIN_C5
#Define CS1 PIN_C6
#Define LCD_RESET PIN_C7
In code no data inputs is define is normal ?

dyeatman · Joined: 06 Sep 2003 Posts: 1941 Location: Norman, OK

The input on pin C3 is going to be a problem because it is a Schmitt trigger
input and 3.3V is not a high enough input level.

My problem is that I am finding conflicting info on the display. One says it is
a parallel data display and another says it has serial.

If you are using the same one as the poster you referenced he is using
parallel data DB0-DB7 on port D, not serial.
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blackmort · Joined: 19 May 2013 Posts: 7

Connect all data pin in PORT D ? i have only quartz 20MHZ i don't can turn my pic to 3.3v ( I have 3.3 V only in db0 and db6 if i turn pic to 3.3V )