Monday, 29 December 2014

2.8 Inch userport display

I connected a bigger 2.8 Inch 8-bit-display with the 328p at the userport.
The transmission to the screen is much faster and I can run some basic-demos on it.
It seems to be a nice display for my mini-c64 :-)

Tuesday, 8 July 2014

Last tiny parts arrived

Today the last tiny parts (eproms) arrived from the USA.
These UV-eproms in CLCC (Ceramic Leaded Chip Carrier) are very rare and hard to find!

All these CMOS-parts are TTL/NMOS-compatible:

  • PLCC Rockwell 65c02 is compatible (not pin-compatible) to the 6510 except the I/O-port. I will use two VIA-outputs to control LORAM/HIRAM.
  • 65c22s will be my replacement for the 6526s. The ports are only exchanged but I have to modify some timer/interrupt programming in the kernal.
  • SDT71024 128k very fast 15ns SRAM as DRAM replacement. I just buyed some rare SOJ-sockets for it.
  • 65C51 as serial interface. An upgrade to the bit-banging RS232 in the real C64.
  • AT27C256 will be my KERNAL/BASIC and an optional expansion cartridge eprom.
  • Atmega 8515 is my SID-replacement: SWINSID - thanks to Swinkels!
  • GAL22V10 as adress-decoder - my PLA ;-)

Tuesday, 24 June 2014

First userport display

At next I connected the Atmega 328p with the 1.8 Inch display to the userport of a real C64.
I built a 2-wire serial connection from the C64 to the AVR. In the AVR is the real C64-characterset. I reduced the character-resolution to 4x5 pixels to fit the 160x128 screen.
All screen-outputs, scrolling, clearscreen, insert, del... are transmitted to the AVR.
Now I have a TFT-C64 ;-)

Saturday, 7 June 2014

1.8 Inch display AVR-test

After the succesful 6502 tests I decided to build a tiny C64 with a small TFT-screen. I want to use an AVR as controller for the screen.
I buyed a very tiny 1.8 Inch display with SPI-interface for the first tests:

Saturday, 31 May 2014

First experience with 6510

My first test of the 6510 was successful.
I connected the 8500 (HMOS 6510) to an eprom, a 555-clock-circuit (right) and a transistor with an LED at the I/O-port.
The first small assembler-loop (written on my C64 with HES-Mon) flashed the LED very fast (without delay) ;-)

You see Phi from the 555 and the I/O-port on the Hameg HM-512:

Friday, 2 May 2014

PCB for Tiny Eprommer 2

The final PCB Rev. B is finished.
I called it Tiny 2.1 because I integrated the adapter for 27c512 eproms in my layout.
My Rev. B circuit is only for 12,5 V cmos eproms:

The 27c512 type and lower/upper half select is switchable.
Assembled and ready to burn:


Thursday, 10 April 2014

I need an EPROM programmer

The first thing I need is an EPROM programmer!
I built the Tiny Eprommer 2 from the famous 64'er magazine from 1984 on breadboard.
...and it works ;-)