BBB-DD-EXAMPLES

• Beaglebone black device driver examples.

Character device driver example(./char_ex/)

• Simple Character device driver example that read/write to kernel memory.

PINMUX/GPIO example(./pinmux_ex/)

• Beaglebone black pinmux register control example.
• Setting some pins to gpio mode(pinmux mode 7).
• Read/Write gpio direction/value by direct register access(No kernel gpio interface)
• Userspace app to test functionality(userapp/pinmux)

INTERRUPT/GPIO example(./interrupt_ex/)

• Beaglebone black interrupt request example.
• Request rising/falling edge interrupt.
• Read/Write gpio direction/value by kernel gpio interface(No direct register access)
• Userspace app to test functionality(userapp/interrupt)

Technical Refernece(Memory-Mapped IO)

• https://www.ti.com/lit/ug/spruh73q/spruh73q.pdf?ts=1666670382560&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FAM3358

ARM Cortex-A8 Memory Map - 177p

ARM Cortex-A8 Interrupts - 543p

Contol Module - 1448p

• CONTROL_MODULE Registers - 1458p
• conf__ Register (offset = 800h–A34h) - 1515p

Timers - 4435p

GPIO - 4976p

• GPIO Registers - 4990p

Resources

Beaglebone black P8 table

• https://github.com/derekmolloy/boneDeviceTree/blob/master/docs/BeagleboneBlackP8HeaderTable.pdf

Beaglebone black P9 table

• https://github.com/derekmolloy/boneDeviceTree/blob/master/docs/BeagleboneBlackP9HeaderTable.pdf

Cape Expansion Header

• https://vadl.github.io/beagleboneblack/2016/07/29/setting-up-bbb-gpio

Device Tree Overlay

• https://github.com/beagleboard/bb.org-overlays/

Extending SD Card Stroage

• https://community.element14.com/products/devtools/single-board-computers/next-genbeaglebone/b/blog/posts/extending-micro-sd-card-space-for-beaglebone-black-use---windows-users

ETC

• https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays

• https://github.com/cdsteinkuehler/beaglebone-universal-io

• https://engineering.stackexchange.com/questions/3980/in-a-device-tree-for-am335x-how-do-i-know-what-pinctrl-values-to-use

• https://www.kernel.org/doc/html/v4.14/driver-api/pinctl.html

• https://github.com/selsinork/beaglebone-black-pinmux

PINCTRL

config-pin -q P8.03 gpio
config-pin P8.03 in
config-pin -q P8.03

config-pin -q P8.04 gpio
config-pin P8.04 out
config-pin -q P8.04

GPIO Sysfs test

echo 0 >/sys/class/gpio/gpio39/value
cat /sys/class/gpio/gpio38/value
echo 1 >/sys/class/gpio/gpio39/value
cat /sys/class/gpio/gpio38/value