From d537c4cfdb0fcfd6da17e88cee7fc819f1a61268 Mon Sep 17 00:00:00 2001
From: Simon Wright <simon@pushface.org>
Date: Sat, 25 Feb 2023 12:56:13 +0000
Subject: [PATCH] Add Microbit accelerometer demo.

This only works for the V1.3B Microbit (assumes accelerometer is MMA8653).

  * test-microbit/Makefile: add accelerometer.
  * test-microbit/README.md: likewise.
  * test-microbit/tests.gpr: likewise.
  * test-microbit/accelerometer.adb: new.
---
 test-microbit/Makefile          |  4 +--
 test-microbit/README.md         |  4 ++-
 test-microbit/accelerometer.adb | 48 +++++++++++++++++++++++++++++++++
 test-microbit/tests.gpr         |  7 +++--
 4 files changed, 58 insertions(+), 5 deletions(-)
 create mode 100644 test-microbit/accelerometer.adb

diff --git a/test-microbit/Makefile b/test-microbit/Makefile
index b8e4e32..f1a9ed4 100644
--- a/test-microbit/Makefile
+++ b/test-microbit/Makefile
@@ -16,9 +16,9 @@
 #  along with this program; see the file COPYING3.  If not, see
 #  <http://www.gnu.org/licenses/>.
 
-all: circle.hex events.hex seconds.hex
+all: circle.hex events.hex seconds.hex accelerometer.hex
 
-circle events seconds: rebuild.stamp
+circle events seconds accelerometer: rebuild.stamp
 rebuild.stamp: force
 	gprbuild -p -P tests
 	touch $@
diff --git a/test-microbit/README.md b/test-microbit/README.md
index 710b18a..0948c13 100644
--- a/test-microbit/README.md
+++ b/test-microbit/README.md
@@ -1,6 +1,6 @@
 # micro:bit tests and demos #
 
-There are three programs built by `make` (or `gprbuild`, but `make` goes on to build hex files that can be dropped onto the micro:bit):
+There are four programs built by `make` (or `gprbuild`, but `make` goes on to build hex files that can be dropped onto the micro:bit):
 
 * `circle` displays a circle running round the LEDs: pressing button A alters the speed, button B alters the direction (clockwise/anticlockwise). The buttons are interrupt-driven.
 
@@ -8,6 +8,8 @@ There are three programs built by `make` (or `gprbuild`, but `make` goes on to b
 
 * `seconds` checks out `Clock` functionality by flashing the centre LED once a second. You get to time a number of flashes with a stopwatch to make sure it really is once a second.
 
+* `accelerometer` displays a single LED: if the card is level, in the centre; as the card is tilted, the lit LED moves to the lowest edge.
+
 The tests interact with the micro:bit hardware using the [Ada\_Drivers\_Library](https://github.com/AdaCore/Ada_Drivers_Library). Configure it using that library's `project_wizard.py`:
 ```
 Welcome to the Ada Drivers Library (ADL) project wizard. This script will
diff --git a/test-microbit/accelerometer.adb b/test-microbit/accelerometer.adb
new file mode 100644
index 0000000..f8ec143
--- /dev/null
+++ b/test-microbit/accelerometer.adb
@@ -0,0 +1,48 @@
+with MMA8653;
+with MicroBit.I2C;
+with LEDs;
+with Ada.Real_Time;
+
+procedure Accelerometer is
+   Acc : MMA8653.MMA8653_Accelerometer (Port => MicroBit.I2C.Controller);
+begin
+   if not MicroBit.I2C.Initialized then
+      MicroBit.I2C.Initialize (S => MicroBit.I2C.S400kbps);
+   end if;
+
+   if not Acc.Check_Device_Id then
+      for R in LEDs.Coord'Range loop
+         for C in LEDs.Coord'Range loop
+            LEDs.Set_One_LED (R, C);
+         end loop;
+      end loop;
+      delay until Ada.Real_Time.Time_Last;
+   end if;
+
+   Acc.Configure (MMA8653.Two_G,
+                  MMA8653.High_Resolution,
+                  MMA8653.High_Resolution);
+
+   loop
+      declare
+         Detection_Limit : constant := 75;
+         Data : constant MMA8653.All_Axes_Data := Acc.Read_Data;
+         use type MMA8653.Axis_Data;
+         use type Ada.Real_Time.Time;
+      begin
+         LEDs.Clear_All_LEDs;
+         if Data.X > Detection_Limit then
+            LEDs.Set_One_LED (3, 1);
+         elsif Data.X < -Detection_Limit then
+            LEDs.Set_One_LED (3, 5);
+         elsif Data.Y > Detection_Limit then
+            LEDs.Set_One_LED (1, 3);
+         elsif Data.Y < -Detection_Limit then
+            LEDs.Set_One_LED (5, 3);
+         else
+            LEDs.Set_One_LED (3, 3);
+         end if;
+         delay until Ada.Real_Time.Clock + Ada.Real_Time.Milliseconds (100);
+      end;
+   end loop;
+end Accelerometer;
diff --git a/test-microbit/tests.gpr b/test-microbit/tests.gpr
index 1458c82..6f91264 100644
--- a/test-microbit/tests.gpr
+++ b/test-microbit/tests.gpr
@@ -1,4 +1,4 @@
---  Copyright (C) 2018, 2020 Free Software Foundation, Inc.
+--  Copyright (C) 2018-2023 Free Software Foundation, Inc.
 --
 --  This file is part of the Cortex GNAT RTS package.
 --
@@ -20,7 +20,10 @@ with "Ada_Drivers_Library/ada_drivers_library";
 
 project Tests is
 
-   for Main use ("circle.adb", "events.adb", "seconds.adb");
+   for Main use ("circle.adb",
+                 "events.adb",
+                 "seconds.adb",
+                 "accelerometer.adb");
    for Languages use ("Ada");
    for Source_Dirs use (".", "../test-common");
    for Object_Dir use ".build";