Re: [Gumstix-users] How do I add a simple HD44780 (or compatible) 16x2 character LCD display?

[Dave H. <dhy...@gm...>]

Hi,

> My group and I are running into the same wall right now, but we don't know how
> to change the HAL layer in order to be compatible with the gumstix. Can we get
> some guidelines?

You can either write a kernel driver or play some games with mmap and
do it directly from user-space.

Start with the robostix/common/lcd-hal-avr.c

The DDR lines in LCD_HAL_Init need to be changed to configure the gpio
lines as outputs.

The LCD_HAL_Delay function needs to be implemented using the
appropriate kernel mode or user-mode sleep function.

And the functions like:

LCD_HAL_E_High
LCD_HAL_E_Low
LCD_HAL_E_Pulse
LCD_HAL_RS_High
LCD_HAL_RS_Low
LCD_HAL_RW_Low
LCD_HAL_Data

need to tweak the appropriate GPIO pins.

That should do it.

-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/