LCD do display - but pins check out

[Tabsoft]

True.

Looking at the EasyPIC5 manual, R/W is tied to ground so you shouldn't read pulses on it.

RS -- RB4
R/W -- GND
E -- RB5
D4 -- RB0
D5 -- RB1
D6 -- RB2
D7 -- RB3

[Scampy]

Thanks for the replies,

OK here's confirmation on how it's wired.

LCD

1 GND
2 +5v
3 +5v via 4K7 resistor
4 RB4 (RS)
5 GND (RW)
6 RB5 (E)
7 - 10 GND (D0 - D3)
11 RB0 (D4)
12 RB1 (D5)
13 RB2 (D6)
14 RB3 (D7)
15 LED+ 5v via 100R resistor
16 LED- GND


I've attached traces of the pulses I get on RB4 and RB5 (sorry I made a mistake in my previous post) and on two of the data lines. I can confirm that the PIC is running as other functions such as RS232 coms and reading the DS18B20's all work fine. I will try a direct wiring option later (wires direct from the PIC pins), but as I can't find any shorts suspect that there is something else that's srewed on the board.

Moral is not to submit gerbers at 1am in the morning after 14 hrs of drafting the design, but to wait a day and check the design with fresh eyes in the morning ! - This board has so many mistakes in it I must of been totally brain dead !!

[Scampy]

Interestingly, I get the same trace when the LCD is returned to the EasyPIC5 board, but on RB5 the pulses are positive going not negative going !!!

[pedja089]

Pin 3 is contrast. And you need to put about 1-2K resistor to ground. Not to Vcc. Or for quick test, just short pin 3 to GND and you will get maximum contrast.
On EasyPIC boards you have trimmer connected to powers supply rails, and slider to LCD. When you just apply power to lcd with correct contrast, first line of display light up all pixels.

[Scampy]

Thanks for the suggestion, but I've tried taking pin 3 to grnd and +5 but it still makes no difference. I've tried wiring the LCd direct to the pins, but still no joy, so I'm at a loss, other than break all the tracks between the PIC and it's header for the LCD, but if there is an issue with the board's through hole plating or something similar then the fault could still be there

[Tabsoft]

What LCD are you using?

[andybarrett1]

What was the board designed in...?

Can you post the project artwork / gerbers at least ?