# BCM2835 UART

The driver at [drv/rpi/uart.fs] wraps BCM2835 "primary" uart with convenience
words. Before using the hardware, it needs to be initialized with
"uart$ ( -- )".

## Example usage

  needs drv/rpi/uart
  uart$
  'x' uart! \ prints "x" to serial link

## API

uart$ ( -- )
  Initialize the hardware. Baud rate is hardcoded at 115200. Interrupts are
  disabled, we're in polling mode.

uart! ( c -- )
  Write "c" to the UART. Block until it's done.

uart@ ( -- c )
  Block until a character is available from the UART, the yield it as "c".

uart@? ( -- ?c f )
  Checks whether a character has been received on the UART. If yes, f=1 and "c"
  is present. Otherwise, f=0 and "c" is absent.
