So, it's been a little while since I updated my blog so I hope this might make up for it. A couple of days ago I put the final touches to my games console.
Some of its features follow: - The unit is 5V DC regulated.
- Its running a Parallax SX-28 Micro-processor @ 80MHz which has 128x 8bit of RAM and 2048x 12bit FLASH memory and 20 I/O pins.
- These I/O pins are separated in to 3 registers/ports 1x 4bit Port-A, 2x 8bit Port-B and Port-C.
- Port-A is connected up to 4 LEDs and a 7-segment LED display.
- Five pins of Port-B are connected up to 5 push buttons arranged in up/down/left/right and fire arrangement, which leaves 3 pins free for expansion. Port-B is also attached to the DB9 connector at the front for connection to a Atari style joystick.
- Each 4pins of Port-C connect to a R2R Ladder network of resistors to create a DAC(Digital to Analog Converter) with fine tuning potentiometers(variable resistors) attached to the output. These two DACs drive the audio and video RTA/Phono connectors.
- There is also and expansion header with 5V, Ground and Port-B attached to it.
- Finally we have a 4pin external serial programming connector and switches to control the power/programming/mpu-reset.
Click to enlarge.
Top right is small camera shot of one of my monitors showing a small test program which generates a composite PAL signal. At the moment I only have monochrome output but I am working on generating a colour PAL-B or PAL-I signal. I will keep you up to date with my progress.
Napalm
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