Arduino: Add pin control and interupts

[mitra42]

Add some words to manage pins.

• Ideally in a manner that would be independent of the board used
• ideally compatible with other people's approaches (so code written for webForth would work on e.g. FlashForth)
• ideally incorporate interrupts
• use the C primitives in Arduino IDE

Some examples of other approaches

• On Flash Forth - not sure if these words are part of FlashForth or just a proposal
• Interupts on Flash Forth
• How Forth handles hardware interuptions ForthHub/discussion#70
• FB/Arduino on registers and https://arduino-forth.com/article/arduino_ATmega328registers?
• YouTube about interrupts on arduino
• WiringPi, An approach taken on top of Gforth and on ForthHub#22

[mitra42]

From https://arduino-forth.com/article/FORTH_FlashForth_pinsDefinition
defPIN ( PORTx mask -- | word -- mask port
high ( PORTx mask -- ; uses mset )
low ( PORTx mask -- ; uses mclr )
output ( pinmask portadr -- ; sets 1 address below portadr)
input ( pinmask portadr -- ; clears 1 address below portadr)
: pin@ ( pinmask portaddr -- fl ; reads 2 addresses below to see whether input using mtst

[mitra42]

From WiringPi: https://github.com/kristopherjohnson/wiringPi_gforth
18 CONSTANT LEDpin
LEDpin OUTPUT pinMode
LEDpin HIGH digitalWrite
See also https://github.com/kristopherjohnson/wiringPi_gforth/blob/master/wiringPi.fs (more specific to Pi)

[mitra42]

Note ESP8266 tests performed on Lolin D1 mini pro (like Wemos) and Arduino on Arduino UNO
Arduino C functions are documented in https://www.arduino.cc/reference/en/language/functions/digital-io/pinmode/
mode = INPUT | OUTPUT | INPUT_PULLUP
INPUT=0 OUTPUT=1 INPUT_PULLUP=2 on Arduino & ESP8266
pinMode(pin, mode)
digitalWrite(13, HIGH);

Also: https://www.arduino.cc/en/Tutorial/Foundations/DigitalPins. summary:

• Defaults to INPUT

Also: https://www.arduino.cc/reference/en/language/functions/analog-io/analogread/
val = AnalogRead(pin) ; range 0..1023

Also https://randomnerdtutorials.com/esp8266-adc-reading-analog-values-with-nodemcu/
which suggests only Analog pin on ESP8266 is A0

See https://randomnerdtutorials.com/esp8266-pinout-reference-gpios/

Most of the ESP8266 development boards have a built-in LED. This LED is usually connected to GPIO2 = D4
On Lolin board BUILTIN_LED is defined as 2

[mitra42]

Straw-person steps

• Try standard blinkplay sketch on Arduino Uno
• Try standard blinkplay sketch on ESP8266 - required using BUILTIN_LED
• Modify sketch to get values INPUT OUTPUT INPUT-PULLUP, HIGH, LOW and define Forth cosntants
• Define constants HIGH LOW
• Presuming same pins, define some forth words
  • pinMode ( pin mode -- )
  • digitalWrite ( pin HIGH | LOW )
• Write simple blink test using loop and delay and test on Arduino & ESP8266
  • : blink BEGIN 500 ms 13 0 digitalWrite 500 ms 13 1 digitalWrite AGAIN ;

[mitra42]

Closing as split subtasks into own issues:

See Analog input #101
See Analog write #102
See Interrupts #103