linuxha / apl

Arduino Peripheral Library for VGA, PS2 and sound. C++ library with low RAM footprint

APL v2.0 – Arduino Peripheral Library

COPYRIGHT (C) 2018-2021 Adrian Kundert
[email protected]

Introduction:

The APL development begun with an hobbyst project having as goal to design a single board computer with audio-video and PS/2 keyboard interfaces. Such open source implementations are already realized by other Atmel programmers like Nick Gammon and Sandro Maffiodo. Since every design is a resource tradeoff and my features priorization were different I came out with a different implementation. Indeed the VGA resolution was important but I wanted to keep the UART port available for communication and also use as less as possible RAM by storing the font/tile data in the PGM memory but which is a bit slower than reading from the RAM.

Features Overview:

• Timer Interrupt based implementation (execution not impacted by the main loop)
• Low RAM footprint by tile rendering from PGM memory (4 clocks / pixel)
• Tile size is 6 px by 8 px (Text mode) or 8 px by 8 px (GraphicPgm and Graphic modes)
• Runtime tile creation for the Graphic mode with tiles allocated in the RAM
• Fast screen horizontal and vertical pixel scrolling for the GraphicPgm and Graphic modes
• Optional hardware pixel multiplexer for RGB capability
• PS/2 keyboard support
• Sound Tone from 45 Hz to 12 KHz
• SD card interface (TBD)

The APL is designed for Arduino software development environement. The hardware configuration is flexible from standart board like Arduino Uno or Nano,

Configuration	Pixel height)	Tile Resolution in Text mode (Pixel width)	Tile Resolution in GraphicPGM mode (Pixel width)	Tile Resolution in Graphic mode (Pixel width)
32 MHz (experimental)	160	29 (172)	19 (152)	17 (136)
24 MHz	160	19 (114)	13 (104)	11 (88)
16 MHz (Uno/Nano)	160	8 (48)	6 (48)	4 (32)

but can also be customized with an higher system clock for better performance. Additionally, an external pixel multiplexer circuit can be added to increase even more the pixel resolution.

Configuration	Pixel height)	Tile Resolution in Text mode (Pixel width)	Tile Resolution in Graphic mode (Pixel width)
32 MHz (experimental)	160	29 (172)	21 (168)
24 MHz	160	20 (120)	14 (112)

Demo

Font (Text mode)

Pong (GraphicPGM mode) and Scolling (Graphic mode)

Sokoban (GraphicPGM mode)

Hardware Configuration

Arduino Uno/Nano board configuration (16 MHz)

Bread board configuration (system clock up to 20 MHz and even more)

Hardware pixel multiplexer (system clock up to 20 MHz and even more)

Atmel Studio 7 Installation

1. Having installed Atmel Studio 7

2. Open the solution file "APL.atsln" for the demo application "Font" or "Pong" or "Sokoban"

3. (if required) in config.h change the sys clock and Pixel_Mux definition:

   #define F_CPU 16000000UL // system clock

   #define PIXEL_HW_MUX // enable this define when Pixel Hardware Mux is used

4. Build and Program your device

Arduino IDE Installation

1. Having installed Arduino IDE version 1.8.10 or newer

2. Import the APL library in your Arduino library folder: menu Sketch -> Include library -> add .ZIP Library

3. Open the demo application "Font" or "Pong" or "Sokoban" with the Arduino IDE

4. (if required) in APLcore.h and config.h change the sys clock and Pixel_Mux definition:

   #define F_CPU 16000000UL // system clock

   #define PIXEL_HW_MUX // enable this define when Pixel Hardware Mux is used

5. Verify and Program your device