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Ada-Arduino-Due

I now have Ada running on my Arduino Due. This comes without all the infrastructure that the Arduino development environment provides. So some research is in order.

This should be considered a working repository. As functions get developed, they will probably migrate to either my BBS-BBB-Ada repository or to the AdaCore Ada_Drivers_library repository.

Current Status

General Purpose I/O

Pins can be configured as digital ouptuts or to support alternate (UART) functions. Digital input should work, but hasn't yet been tested. Since the on-board LED is connected to one of the GPIO pins, it can be flashed.

Serial ports

The serial driver supports all four available serial ports on the Arduino Due. Transmit and Receive is supported by both polled and interrupt driven drivers. The interrupt driven driver also supports RS-485 mode, character echo, and backspace and delete keys. This should provide the basics for both console I/O as well as serial communication with other devices.

I2C

I2C reads are interrupt driven. I2C writes only have a single byte write that is partially polled. These are also available in an object oriented version. The write needs to be converted to fully interrupt driven and a block write added.

The interface is moving in the direction of the I2C interface in BBS-BBB-Ada, though some changes will probably be required there. Once the interfaces match, all the I2C devices from BBS-BBB-Ada should work.

A BME280 is used for testing and some functions are working. Note that 64 bit arithmatic is required for the BME280.

Analogs

Initial version of analog inputs is available. Note that the internal channel numbers don't match the Arduino pin numbers. Since 16 channels are defined and only 12 are actually used, there are four unused channels. Enabling one of them seems to cause problems with the I2C interface and with tasking.

Analog outputs are working on both channels. Note that currently analog inputs operate in the free running mode and analog outputs use a polled wait. This will probably be enhanced sometime in the future.

Tasking

Moved the LED flasher into a separate task - multiple tasks are working.

Lisp

The Tiny-Lisp interpreter has been incorporated and operations have been created for accessing some of the hardware. These can be used as examples for creating your own.

The (peek) and (poke) operations have been tested. Using (poke) to set discrete output values with:

  1. (dowhile (= 1 1) (set-pin 25 0) (set-pin 25 1))
  2. (dotimes (n 1000000) (set-pin 25 0) (set-pin 25 1))
  3. (defun set-25 (value) (if (= 0 value) (poke32 #x400E1434 #x01) (poke32 #x400E1430 #x01))) (defun toggle (count) (pin-mode 25 1) (dotimes (n count) (set-25 0) (set-25 1)))
  4. (defun toggle (count) (pin-mode 25 1) (dotimes (n count) (poke32 #x400E1434 #x01) (poke32 #x400E1430 #x01)))

Measuring discretes with an oscilloscope,

  1. dowhile toggles about 10kHz
  2. dotimes toggles about 15kHz
  3. toggles about 3kHz
  4. toggles about 15hKz
  5. A similar loop in Ada was measured about 384kHz

The timing differences should give a little idea of the overhead of different Lisp operations.

Command Line

You can login by typing anything as the user name and "override" as the password. The user name will be used as a command prompt. Internally, all commands are converted to upper case before processing. At the command line, there are some commands that may or may not be useful:

  • LOGOUT, LOGOFF, BYE - These commands all return to the username prompt.
  • FLASH <number> - Sets the number of times the LED flashes
  • EXIT, QUIT - Don't do much
  • INFO - Prints the CPU info
  • HELP - Doesn't help
  • SERIAL - Sends a message out on serial lines 1, 2, and 3.
  • ANALOG - Prints values of the analog inputs and cycles analog outputs
  • I2C - I2C related commands
  • STOP - Stops tasks
  • START - Starts tasks
  • GPIO - GPIO related commands
  • STATUS - Prints system status
  • LISP - Enters the Tiny Lisp interpreter.

Lisp

The following Lisp operations are added.

  • (due-flash <number>) - Sets number of times for LED to flash
  • (set-pin <pin number> <state 0 or 1>) - Sets digital output pin to specified level
  • (pin-mode <pin number> <mode 0 or 1>) - Sets digital pin 0 = input, 1 = output
  • (read-pin <pin number>) - Returns the state of a digital pin
  • (read-analog <analog input>) - Returns the value of an analog input
  • (info-enable) - Turns on some debugging information
  • (info-disable) - Turns off some debugging information
  • (read-bmp180) - Returns temperature (in tenth of a degree C) and pressure (in Pascals) from BMP180 sensor
  • (set-pca9685 <pin> <value>) - Sets PWM value for the specified PCA9685 pin.
  • (read-l3gd20) - Returns x, y, and z rotation rates in tenth of a degree per second.

Dependencies

The material in this repository depends on the following other repositories:

License

This software is available under GPL 3. If you wish to use it under another license, please contact the author. Note that the files with the names sam3x8s*.ads have been autogenerated from the SAM3X8S SVD file, with some minor modifications. I have no claims to these file.