Posted on July 27th, 2014
I recently bought some PICs for a project – the devices in question being the fairly recent 16F1829 variety. (Reasons: Cheap, 32MHz, 20 pins, can self-program, 8K code RAM, 1K data, 2 x SPI ports – all good stuff). Having used the 16f627 for quite some time, a few things were immediately noticeable:
1. These things are packed with peripherals and the datasheet goes on forever!
2. A new-ish version of MPLAB is required. At first I downloaded MPLAB X – Oh man.. What a bloated, over-complicated, C-orientated mess. Sorry Microchip, it’s awful! Fortunately older versions of MPLAB are still available and v8.92 did the trick. The trick being, you know, ” Enter some code, click build, burn to chip”. Simples.
3. My venerable DIY Tait Classic parallel port programmer wont do. WinPIC800 supports the 16F1829 but only with their proprietary hardware so I ended up buying a clone of the PICkit3 which included a ZIF adapter for standalone programming. Check Ebay etc.
4. There wasn’t a massive amount of example code on the net, so the first thing I did was make my own template. It’s here if you want to use it.
Anyway, the chip appears to do what I need so hopefully development can now begin..
Posted on June 9th, 2014
Thanks to me ol’ buddy and web design guru Dick Dolby, my little retro components shop now has a proper ecommerce front end. Soooo.. if you need parts for Spectrum / Commodore – please take a look. I also offer keyboard repairs and composite video mod service for the Spectrum, and recapping service for both Speccy and Commodore 64.
Posted on June 5th, 2014
Well I ended up needing 40+ Pendulum PCBs. This would have been too much work to make at home even as single-sided board so I had a browse around for a low-cost production house to have them professionally made. Didn’t take long to find PCB.HQEW.NET, who are cheap and efficient – it only took a week or so for the boards to arrive from China once dispatched. Highly recommended!
Posted on May 15th, 2014
Following an enquiry from Spectrum emulation whizz Alessandro Dorigatti, I’ve made a small daughterboard for the V6Z80P that provides 28.000MHz and 28.375MHz clock signals – IE: perfect for the Spectrum and Spectrum 128.
Although we’ve had very respectable Speccy emulation before now, further development was becoming tricky since the internal FPGA clocking was a based on a kludge to obtain higher clocking from the 14MHz and 16MHz oscillators available by default on the V6 (these values were below the magic 25MHz at which the Spartan II’s internal multiplier/divider PLLs can be used.) One immediate result is that the Spectrum 128 emulator now shows pixels of the correct aspect ratio, but hopefully it’ll open up future development too (I’m glad I added those unused GCLK pin headers now:)
The board is at present a home-etched affair, but there are plans afoot to get it made professionally to better match the V6Z80P. It’s a very simple circuit based on biased 74HC04 gates – It just took a bit of experimentation to get them oscillating correctly (at the high end of the 74HC logic @ 3.3v, not all brands of logic IC are equal, it would seem.)
Posted on May 10th, 2014
With all my recent tinkerings with ZX Spectrums and Commdore 64s I thought I may as well make it possible for others to buy as many spares as possible in one place – to that end I have opened a little spares shop.