Flex_LCD Crashing

Geps · Joined: 05 Jul 2010 Posts: 129

Hi,

I'm using the Flex 20x4 LCD with a 18F4520. CCS Compiler version 4.087.

I have my pin defines as follows:

Ttelmah · Joined: 11 Mar 2010 Posts: 19359

Removing the RW pin enable, means that the code doesn't try to read from the display to see if it is ready, but instead just delays for enough time for the byte to be sent. In the former case, if it is not 'seeing' a "I am finished" from the display, the code will hang.
To wake the display up, the code sends standard initialisation strings, and waits for each byte of these, with either a fixed delay, or waiting for the busy response to finish if R/W is enabled.
So, you are _not_ getting correct data responses from the display.
Possible reasons:
1) Faulty display.
2) Faulty wiring.
3) Voltage/configuration problem.
4) Timing.

Now, '4', applies particularly to some more recent displays, that seem to need longer to initialise than the original Hitachi controller. Add a significant extra delay before calling the lcd_init, and see if this helps.
On '3', you need to get a real data sheet for the display. Does it's outputs drive to a level compatible with the PIC's inputs on the pins you have selected?. All the inputs you have selected, are Schmitt type. Are you sure you have turned off the SPI, that is otherwise connected to a couple of the pins (the output from the wizard, is usually 'wrong' for this.....)?. Are you sure you have turned off the PSP?.
2) Obvious - check again, and triple check no wires are shorting to one another - pin to pin, and wire to wire with a meter.
1) Always possible......

Best Wishes

Geps · Joined: 05 Jul 2010 Posts: 129

Thanks Ttelmah, I took your advice about the port pins and changed the pins from Port C to Port B which seems to have fixed it.