I’d like to use UART1 to control an external modem using the following signals:
GPIO4 = U1_RXD
GPIO5 = U1_TXD
GPIO6 = U1_CTSn
GPIO7 = U1_RTSn
I’ve found that /debug/gpio tells me that at present these are set up as GPIOs. How do I set them up as ALT_A?
I tried writing to /debug/gpio
echo "gpio-4 (u1rxd ) in hi altA pull" >/debug/gpio
But that hasn’t updated the gpio file.
Thanks you for your help.