Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/brentseidel/bbs-bbb-ada

A collection of Ada sources for working with Linux based embedded computers, such as the BeagleBone Black or Raspberry Pi
https://github.com/brentseidel/bbs-bbb-ada

ada beaglebone-black embedded-linux embedded-systems raspberry-pi

Last synced: about 1 month ago
JSON representation

A collection of Ada sources for working with Linux based embedded computers, such as the BeagleBone Black or Raspberry Pi

Awesome Lists containing this project

README 

        
# BBS-BBB-Ada

This repository contains a collection of Ada sources for working with embedded

Linux computers such as the BeagleBone Black or the Raspberry Pi, as well as the

ARM based Arduino Due.  Due to differences between platforms and the limited

amount of time I have to work on things, something may work on one platform,

but not on another.



[![Alire](https://img.shields.io/endpoint?url=https://alire.ada.dev/badges/bbs_embed_common.json)]

(https://alire.ada.dev/crates/bbs_embed_common.html)



[![Alire](https://img.shields.io/endpoint?url=https://alire.ada.dev/badges/bbs_embed_linux.json)]

(https://alire.ada.dev/crates/bbs_embed_linux.html)



# Notices

## Note

As a result of bringing in the Arduino Due, the non-object oriented interfaces

will generally be going away.  They may still exist at a low level, but are

not recommended for use.



## Note

Due to changes in the way that various I/O is handled, these routines are pretty much

guarenteed not to work on some versions of Linux.  The I2C routines were developed on

Debian Jessie, Linux V4.1.12-ti-r29 and use Ada 2012.



## Note

Some of the system files that control I/O are owned by root and do not allow world

write access.  A shell script is provided to set the permissions so that the Ada

program does not need to run as root.



## Note

I finally got around to developing a centralized units system.  The types for

many physical units are now defined in the BBS.units package.  This can be fetched

from the https://github.com/BrentSeidel/BBS-Ada.git repository on GitHub.  While

this adds an external dependancy for this repository, the result is that by using

it, all packages will have access to the same units, conversions, and functions.



An advantage of this approach is that if you use the proper units in your

calculations, the compiler will be able to catch mismatches between feet and

meters before you crash your probe into Mars.



## Note

Another reoganization is likely in work.  These routines seem to work fairly well on

Linux based embedded systems.  I am getting interested in trying out Ada on bare

ARM based systems such as the Arduino Due.  It would be nice to be able to re-use

some of this software.  The approach that I'm currently thinking of is to use abstract

base clases for the various types of I/O such as i2c or gpio.  These would define the

basic interface routines for these I/O.  The concrete classes would contain the

specific code for these I/O.  Thus, for example, there would be a base gpio class and

then a concrete gpio.linux class and a concrete gpio.arduion_due class.  This might not

be a big advantage for gpio, but for i2c it would mean that I don't need to update any

of the routines for the various i2c devices.  This will require a bit of planning and

experimentation.



# Contents

## LEDs

This works only on the BeagleBone Black which has four controllable LEDs on the

circuit board.  The BBS.embed.LED package contains definitions and routines for

controlling the four built-in LEDs on the board next to the ethernet connector.



## i2c

The BBS.embed.i2c package contains a set of objects and routines for reading and

writing to devices on I2C buses.  To actually use the I2C bus, you must create

an object from either the BBS.embed.I2C.Due or BBS.embed.I2C.Linux packages.



**Note** after a bug fix, the I2C interface works on a Raspberry PI 3.  It should

work on other models as well.  Just pass "/dev/null" as the pin control files.  A

configuration routine has been provided that omits the pin control parameters.

The Linux version tested are:

* Raspberry Pi-3 Linux 4.4.13-v7+ #894 SMP Mon Jun 13 13:13:27 BST 2016 armv7l GNU/Linux

* Raspberry PI 4 Linux 5.15.0-1033-raspi #36-Ubuntu SMP PREEMPT Thu Jun 22 08:10:31 UTC 2023 aarch64 aarch64 aarch64 GNU/Linux



## i2c subpackages

Subpackages have been created for the following devices to provide a higher level interface.



### ADS1015

This is a four channel 12 bit Analog to Digital Converter.  The four channels

can be used individually in a single ended mode.  Channel 0 and 1 can be

paired for differential measurements.  Channels 0, 1, and 2 can be paired

with channel 3 for differential measurements.  The 12 bit value is a signed

twos complement format.  This means that for single ended conversions, it

is effectively 11 bits.



### BME280

This chip contains pressure, temperature, and humidity sensors along with calibration

values.  The package contains an object oriented interface to retrieve calibrated

measurements from the sensors.



### BMP180

This chip contains a pressure sensor and a temperature sensor along with calibration

values.  The package contains both an object oriented and non-object oriented

interface to the sensors to retrieve calibrated measurements.



### L3GD20H

This is a gyroscope on a chip.  Routines are provided to configure the chip and to get

the rotation around the X, Y, and Z axis.  A routine is also provided to return all

rotations in a single record.



The chip also contains an temperature sensor and a routine is provided to access it.



### LSM303DLHC

This chip contains a 3 axis accelerometer and a 3 axis magnetometer.  Routines are provided

to initialize the chip and to return the acceleration or magnetic field for each axis.

Combined acceleration or magnetic field for all three axis can also be returned.



The chip also contains a temperature sensor and a routine is provided to access it.



### MCP4725

This is a single channel 12 bit DAC.  The fast write and write commands

have been tested and work.  The other features are likely to work, but haven't

been tested.



### MCP23008

This is an 8 bit I/O expander.  It can be used to add 8 GPIO pins per adapter.



### MCP23017

This is a 16 bit I/O expander.  It can be used to add 16 GPIO pins per adapter.



### PCA9685

This is a 16 channel, 12 bit PWM controller.  Basic functions seem to work, but

this should be considered to be under development and even more experimental than

every thing else.  The basic function is available, more features are expected

to be added as I have time and energy.



### Devices

This package contains constants for other devices that do not yet have individual packages.



## GPIO

This is an object oriented interface to the GPIO pins.  It allows setting or

testing a pin.  This uses the /sys filesystem interface and this is not particularly

high performance.  It should be adequate for lighting indicators or checking the

state of switches.



The GPIO have now been tested to work on a Raspberry PI 3 as well as a BeagleBone

Black.  Using the following code to toggle a gpio as fast as possible:

~~~~

loop

   gpio.set(1);

   gpio.set(0);

end loop;

~~~~



I got the following results:



| System | Frequency |

|--------|-----------|

| BeagleBone Black | 60 kHz |

| Raspberry PI 3 | 160 kHz |

| Raspberry PI 4 | 657 kHz |

| Arduino Due | 384 kHz |



Note that the times are only approximate and can vary greatly depending on other

processing on the processor.



Note that the Raspberry Pi used the V2 ioctl() interface to GPIO while the BeagleBone

Black and Raspberry Pi 3 used the sysfs interface.



By way of comparison, an Adruino Mega 2560 got 126.6kHz or 128.2kHz (it toggled between

the two as I measured it) in a similar tight loop using digitalWrite().



### TB6612

This is used to control a stepper moter using 4 GPIO pins.



## PWM

This is an object oriented interface to the PWM controllers.  The BeagleBone

Black processor has 8 PWM controllers.  Due to the lack of a pinmux structure

for P8_28, one of the PWMs is not really usable.  The interface allows control

of the period (or rate) and the time high (or duty cycle) of the PWM output.



## Analog inputs

This is a simple object oriented interface to the analog inputs.  This base

class supports 12 bit conversions.  The concrete implementations for Linux or

Arduino Due may support other options.



On the BeagleBone Black, there are seven analog inputs available and the pins

that they are on are fixed purpose.  The A/D converter is a 12 bit converter,

so the result should be in the range 0..4095.



The Arduino Due has 16 analog inputs, 12 of which are actually wired up and are

available for use.  The A/D converter is a 12 bit converter.



## SPI

A basic API for the SPI interface is provided.  It does 8 bit reads and writes

using the default settings from Linux.  It has been tested on a Raspberry PI 3

and works well enough to interface with the AdaFruit RA8875 breakout board so

more features have not yet been developed.



### RA8875 LCD driver

This provides an interface to the RA8875 LCD driver and touchscreen interface.

It should be considered to be experimental.  Bugs are to be expected and full

functionality is not provided.  Drawing of most built in geometric shapes is

supported.  Text drawing is supported, but occasionally gets garbled.  I am

trying to figure this out.  Touch is supported with calibration, but to be

really useful will need filtering and debouncing.  If I get ambitious, I may

build a widget set on top of this.



**Note** When using the AdaFruit breakout board with the Raspberry PI 3 (and

probably any other 3V system, the power supply needs to be 5V.  The RA8875 itself

seems to work at 3V, but the backlight driver needs 5V.  This was a pain to debug.



**Note** The RA8875 does not tri-state the MISO line.  Thus it cannot share a SPI

interface with other devices without an additional tri-state device.



#### RA8875 Widgets

This is currently only a figment of my imagination.  I hope to eventually provide

some basic widgets for a touch interface.