Vintage Programmer Gets Modern Chip Adapter

While trying to revive a Donkey Kong Jr arcade board, [Jelmer Bruijn] found himself in the market for an EPROM programmer and became the proud owner of a 1990’s era Dataman S4. Despite its age, it’s a fairly nice tool which allows you to read and write a laundry list of different EPROM types, all without being tied to a computer. The only catch is that a few types of chips need an adapter to work in the Dataman S4, some of which are unsurprisingly no longer available.

After some above and beyond support from the current crew at Dataman set him on the right track, [Jelmer] decided to try his hand at reverse engineering how the old adapters worked so he could build his own. His ultimate goal was to read 40 pin EPROMs on the 32 pin Dataman S4, but in the end he says the information he gathered should be applicable for building other adapters if you ever find yourself in need of such things.

As you might expect, there’s a bit more to the project than a simple pin adapter. [Jelmer] assumed some kind of shift register or latching arrangement would be required to make up for the shortage of pins on the Dataman S4’s ZIF socket. It was just a matter of figuring out how it all went together.

Luckily, [Jelmer] found that the programmer would happily attempt to perform operations on a 16 bit EPROM even though no adapter was physically present. This gave him a chance to probe around with a logic analyzer to figure out what it was trying to accomplish. The trick turned out to be splitting the 16 bit bus into two 8 bit buses which are requested sequentially.

With careful observation, close studying of 16 bit chip datasheets, and much brow furrowing, he was eventually able to come up a design that used five 74xx573 latches and put a schematic together in Eagle. There were a few kinks to iron out when the boards finally arrived, but ultimately the design worked on the first try. [Jelmer] says the same technique should work for 42 pin EPROMs, but as Dataman still actually sell adapters for those he decided not to supply schematics for it.

[Jelmer] tells us that he was inspired to send this success story our way after reading how our very own [Elliot Williams] took the long away around to erase a couple UV EPROMs recently While this isn’t the first time we’ve seen somebody have to hack support for 16 bit EPROMs into their programmer, it’s good to see that the manufacturer at least had the customer’s back in this case.

8-Bit Chip Rocks 16-Bit 44.1kHz Tunes

There’s a special place in our hearts for chip tunes generated with your favorite microcontroller. But why stop there? Full-featured audio is a great challenge and it’s not often we see examples of this caliber. It puts out CD-quality audio using not much more than a microcontroller.

How do you get 16-bit audio out of an 8-bit microcontroller. We’ll give you a hint: two pins are used. Not helping? Here it comes: two 8-bit DACs PWM outputs are used on this chip, the ATmega1284. One is used for the lower eight bits, the other handles the upper. The two are combined using carefully calculated precision resistor values and the results are beyond what you imagine. This is produced at a bitrate of 44077.135, slightly off from the 44100Hz standard but we challenge you audiophiles to tell the difference. The wave files are served from an SD card read by the chip using the Petit-FatFs library.

There are so many great things about this project. First off, following [Wancheng Zhou’s] example will let anyone with even basic microcontroller skills build a digital audio player for an [Andrew Jackson] and a couple of [Washingtons]. Secondly, those with a medium uC skill level will want to take the idea and implement/debug it for themselves. Bringing it home, [Wancheng] shows how to gauge the quality of the audio output using FFT.

If you didn’t figure it out by the time of year, this is yet another example of a Cornell ECE 4760 final project. Shout out to [Bruce Land] for inspiring awesome projects and requiring extensive documentation of the projects which itself promotes deeper understand all around.

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16-bit HCMOS Computer Is A Wire Wrapping Wonderland

The D16/M is a 16-bit computer built using HCMOS logic chips. It’s a thing of beauty from every angle thanks to the work [John Doran] put into the hobby project. But he didn’t just take pictures of the build and slap them on a webpage. He took the time to publish a remarkable volume of documents for the computer too!

The processor can execute a total of 73 instructions and offers a 100-pin bus for accessing main memory and peripherals. So far he has documented three different peripheral boards, each of which is pluggable thanks to an edge connector that accepts the board. The expansion boards are for system memory, serial communication port, and a clever four-position SD card interface for persistent storage.

Got a question about the system? He wrote a FAQ. Want to learn from his obvious mastery of wire-wrapping? He wrote a wire wrapping tips guide. Like we said, there’s a mountain of documentation and the links to it all are included in his main project page.

[Thanks Allen]