Using a uLCD-32PT display with the Beaglebone?

Hello everyone, I've been searching around how utilize the GPIO
pins(or is it more accurate to say UART pins?) and I'm having little
luck on talking to this LCD display:
with the BeagleBone.... If i could just figure out how to send just
one command that would be great I can take it from there.

I tried using this guide
but with the Beaglebone pins and no success has occurred just yet.

If maybe i could get a good tut on using GPIO pins that would be great
too google(or any other search engine) provide little results.

Thanks everyone I hope to help contribute back to the community when I
get some knowledge, skills and/or experience under my belt! :smiley:


I've been able to power the LCD display by connecting the VIN to the
BeagleBones SYS_5V pin # 7 located on expansion header P9. Then I
connected the LCD display's GND (ground) pin to the BeagleBones GND
pin # 1 located on expansion header P9.

I'm thinking I need to connect the LCD display's RX pin to the
Beaglebones UART1_TXD pin # 24 located on expansion header P9 then
connecting the LCD TX pin to the BeagleBones UART1_RXD pin # 26
located on expansion header P9 does that sound right?

The GPIO functionality is well abstracted by the kernel and is almost
no different from the earlier beagleboards once you configure the
correct pin mux mode for your GPIO pin. This can be done from debugfs
like in [3] or from the kernel (refer to

The Beaglebone has 128 GPIO pins on 4 banks (32 on each bank). So you
would translate GPIO X_Y in the schematic to GPIO number X*32 + Y

This is how kernel does it as well:
/* Convert GPIO signal to GPIO pin number */
#define GPIO_TO_PIN(bank, gpio) (32 * (bank) + (gpio))

Then follow the instructions at [1] to export and access GPIO from
userspace (example at [2]).



Thank you so very much! I haven't tested out anything you said just have cleared up all my current questions as well as cleared up
all my confusion on this GPIO pin stuff and all it's mystery!
I hope to write a tutorial and/or library (maybe a cape too!) for
these LCD displays and learning how the pins work will help progress
speed up a little. Thanks again mate!

Plus a bb gpio to the lcd reset.