The code is released under the MIT License.
6502 code for estimating roll and pitch using an IMU.
Several InvenSense sensors are supported. Including MPU-6500, MPU-9250 or ICM-20689.
The hardware is based on Ben Eater's excellent YouTube series: https://eater.net/6502.
The original schematic can be found in img/6502.png.
The switches on PA0-PA3 has been removed and are used for bit baning SPI. This is used for communicating with the IMU.
The pins are connected according to the following table:
| 6502 | IMU |
|---|---|
| PA0 | CLK |
| PA1 | MOSI (SDI) |
| PA2 | MISO (SDO) |
| PA3 | CS (NCS) |
| NMI | INT |
Furthermore an optional LED can be connected to PA4, which is blinked every 10 ms using the Timer1 interrupt inside the W65C22 (Versatile Interface Adapter (VIA)).
To build and flash the application simply run:
make flashThe image below shows the output from the program on the LCD display:
The first two values are the roll and pitch angles respectively. The angle will be in the range 0-255, thus 90 degrees corresponds to a value 64.
The bottom three values are the top 8-bits of the x,y,z-axis accelerometer values respectively.
The vasm assembler is used.
The latest release can be downloaded here: http://sun.hasenbraten.de/vasm/index.php?view=relsrc.
The code is compiled for the 6502 CPU and is using the oldstyle syntax module:
make CPU=6502 SYNTAX=oldstyle
sudo cp vasm6502_oldstyle /usr/local/bin/More compilations instructions can be found here: http://sun.hasenbraten.de/vasm/index.php?view=compile
minipro is used for programming the EEPROM.
It can be compiled and installed on a Debian/Ubuntu system like so:
sudo apt install build-essential pkg-config git libusb-1.0-0-dev
git clone https://gitlab.com/DavidGriffith/minipro.git
cd minipro
make
sudo make install
sudo cp udev/*.rules /etc/udev/rules.d/
sudo udevadm trigger
sudo usermod -a -G plugdev $USERFor more information see the minipro README