Title: I2C support for LCD Backback
Post by: shuckc on November 23, 2011, 04:03:58 pm
Post by: shuckc on November 23, 2011, 04:03:58 pm
I was looking at modifying the LCD backpack to drive a 12864H Graphics LCD from Sparkfun/SK Pang (UK) today http://www.skpang.co.uk/catalog/graphic ... p-542.html (http://www.skpang.co.uk/catalog/graphic-lcd-128x64-stn-led-backlight-p-542.html) . This needs some work as the LCD uses a 20pin header and needs chip select and control wires driving so the PIC is a little undersized.
While looking at the existing board design I spotted that it would be pretty easy to add add I2C support. Pins RB0 and RB1 (that support I2C) are hard wired to the LCD data bus, whilst pins RB4 and RB5 are run to GPO pin headers. It's fairly simple to swap them over and have RB0 and RB1 available for GPO.
LCD-Backpack-PIC-HD44780-I2C-v1a.brd and LCD-Backpack-PIC-HD44780-I2C-v1a.sch
Does anyone want to review the schematics/board? I'm not sure I would use it myself but it might be interesting to make a couple of PCBs with this design (I2C-v1a):
[attachment=1]
Edit Original schematic (v1b):
[attachment=0]
http://dangerousprototypes.com/docs/ima ... 80-v1b.png (http://dangerousprototypes.com/docs/images/e/e6/Cct-LCD-Backpack-PIC-HD44780-v1b.png)
While looking at the existing board design I spotted that it would be pretty easy to add add I2C support. Pins RB0 and RB1 (that support I2C) are hard wired to the LCD data bus, whilst pins RB4 and RB5 are run to GPO pin headers. It's fairly simple to swap them over and have RB0 and RB1 available for GPO.
Code: [Select]
Pin dig anan I2C SPI IntI've amended the schematic and board layout to swap over these pins and checked into DP SVN http://code.google.com/p/dangerous-prot ... 2Fhardware (http://code.google.com/p/dangerous-prototypes-open-hardware/source/browse/#svn%2Ftrunk%2FLCD_Backpack_PIC_HD44780%2Fhardware)
21 RB0 AN12 SDA SDI INT0
22 RB1 AN10 SCL SCK INT1
25 RB4 AN11 -- -- KBI0
26 RB5 -- -- -- KBI1
LCD-Backpack-PIC-HD44780-I2C-v1a.brd and LCD-Backpack-PIC-HD44780-I2C-v1a.sch
Does anyone want to review the schematics/board? I'm not sure I would use it myself but it might be interesting to make a couple of PCBs with this design (I2C-v1a):
[attachment=1]
Edit Original schematic (v1b):
[attachment=0]
http://dangerousprototypes.com/docs/ima ... 80-v1b.png (http://dangerousprototypes.com/docs/images/e/e6/Cct-LCD-Backpack-PIC-HD44780-v1b.png)
Title: Re: I2C support for LCD Backback
Post by: ian on November 25, 2011, 08:37:17 am
Post by: ian on November 25, 2011, 08:37:17 am
Very cool adaptation, thanks or sharing and uploading to SVN!