Topic summaryGPIO Expand Summary Extracted from the Wikipedia article General-purpose input/output. External linksGPIO framework for FreeBSDArchived 5 September 2017 at the Wayback MachineFreeBSD gpio(3) API manualFreeBSD gpioctl(8) manualFreeBSD gpio(4) manualALSA Development ListLinux Kernel Doc on GPIOLinuxTV GPIO Pins Info Wikipedia source
