NED8PC

It is a card containing 60kB of RAM and 8kB of EEPROM, divided into two banks of 4kB switched by a jumper on the board.

The card offers a monochrome display in text mode of 80 characters per 24 lines and graphics with a resolution of 480 x 288 pixels.

Serial port card at 9600bps. More information on the website ARZE.cz

First output card to test the functionality of my NED8PC computer.

The card contains only the most important components: 8 LEDs with resistors, a 74HCT574 output latch and an address decoder consisting of 75154 (54145 - 1 of 16 decoder), 74LS32 (4x OR) and 74LS14 (6x NEG). And of course a couple of 100nF capacitors.

The address of the card is 00h and is addressed as an output device by the OUT instruction.

I made some progress and at least printed new labels on the front panel.

The card itself contains a CPU UA880D which is a clone of the Z80 CPU operating at up to 4MHz. Furthermore, an oscillator with a frequency divider with the possibility of adjustment with a jumper. And a reset circuit.

Unfortunately, I didn't avoid using wire jumpers, which also have to be this long due to an error in the design (I didn't make holes for them). In addition, I chose the wrong spacing of the CPU socket, so I also made a reduction.

Thanks to PCBway, I was able to make a professional PCB for another card, the NED8CPU.

The card is double-sided, metallized, including printing, and was at home within 2 weeks of ordering.

Now I will install and test :-)

This is a card with 64 KB of RAM memory.

I finished the DMA memory write card and faceplate

The labels on the front panel are still provisional.