This egg provides an interface to the RaspberryPi GPIO pin for CHICKEN Scheme.
You'll need to install Wiring Pi before using this library. The Wiring Pi documentation may help you understand some of these functions in more detail.
No eggs required. (This egg was written to reduce the huge dependency list of the original.)
(use raspberry-pi-gpio)
(setup-gpio)
;; digital read / write
(pin-mode 1 'output)
(digital-write 1 HIGH)
(digital-write 1 LOW)
(printf "Pin 1 is: ~S~n" (digital-read 1))
;; using interrupts to respond to events
(set-edge 7 'falling)
(set-edge 8 'both)
(define (loop)
(receive (pin value intsec intnsec) (receive-gpio-event)
(printf "Interrupt on pin ~S, interrupt time ~S.~S, value: ~S, value now: ~S ~n"
pin intsec intnsec value (digital-read pin))
(loop)))
(loop)One of the setup functions must be called at the start of your program, or your program will fail to work correctly.
Use the Broadcom GPIO pin numbers when referencing pins.
Use the wiringPi pin numbering scheme. This is a simplified numbering scheme which provides a mapping from virtual pin numbers 0 through 16 to the real underlying Broadcom GPIO pin numbers. See the Wiring Pi documentation for more info.
Use the physical pin numbers on the P1 connector only.
Use the /sys/class/gpio interface rather than accessing the hardware directly. This can be called as a non-root user provided the GPIO pins have been exported before-hand using the gpio program.
Returns the board revision (1 or 2).
Sets the pin to the given mode. Mode is one of the following symbols:
input, output, pwm-output, gpio-clock.
This sets the pull-up or pull-down resistor mode on the given pin, which
should be set as an input. Pud should be one of the following symbols:
off, up, down.
Writes the value to the PWM register for the given pin. The Raspberry Pi has one on-board PWM pin, pin 1 (BMC_GPIO 18, Phys 12) and the range is 0-1024. Other PWM devices may have other PWM ranges.
This function is not able to control the Pi’s on-board PWM when in Sys mode.
Writes the value HIGH or LOW (1 or 0) to the given pin which must have been previously set as an output.
Writes the value HIGH or LOW (1 or 0) to the given pin which must have been previously set as an output.
Returns two values, seconds and nanoseconds since process- or machine startup when the pin value was changed.
This function returns the value read at the given pin. It will be HIGH or LOW (1 or 0) depending on the logic level at the pin.
This writes the given value to the supplied analog pin.
This returns the value read on the supplied analog input pin.
Sets up an interrupt handler for the pin and given edge using wiringPiISR.
Use this to hook up events for use with recieve-gpio-event.
Type should be one of the following symbols: falling, rising, both,
setup. If setup is used then no initialisation of the pin will happen –
it’s assumed that you have already setup the pin elsewhere (e.g. with the
gpio program).
Blocks until a GPIO interrupt occurs on a pin that had set-edge called on it.
Returns four values the pin number that caused the interrupt, the value read from the pin in the interrupt routine, the number of seconds and nanoseconds representing the time when the interrupt routine was executed.
Returns two values the number of seconds and nanosecons since process- or machine startup.
Uses Linux' clock_gettime to read CLOCK_MONOTONIC_RAW, i.e. the
result value is not effected by adjustments from NTP etc. and
therefore suited to measure physical time deltas.
The HIGH value (1) exported by wiringPi.
The LOW value (0) exported by wiringPi.
Caolan McMahon, Jörg F. Wittenberger
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the Software), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED ASIS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.