Chip Shortage Engineering: Misusing DIP Packages

October 3, 2023 by Tom Nardi 57 Comments

After years of seeing people showing off and trading their badge Simple Add-Ons (SAOs) at Supercon, this year I finally decided to make one myself. Now for a first attempt, it would have been enough to come up with some cool PCB art and stick a few LEDs on it. But naturally I started with a concept that was far more ambitious than necessary, and before long, had convinced myself that the only way to do the thing justice was to have an onboard microcontroller.

My first thought was to go with the venerable ATtiny85, and since I already had a considerable stock of the classic eight-pin DIP MCUs on hand, that’s what I started prototyping with. After I had something working on the breadboard, the plan was to switch over to the SOIC-8 version of the chip which would be far more appropriate for something as small as an SAO.

Unfortunately, that’s where things got tricky. I quickly found that none of the major players actually had the SMD version of the chip in stock. Both DigiKey and Mouser said they didn’t expect to get more in until early 2024, and while Arrow briefly showed around 3,000 on hand, they were all gone by the time I checked back. But that was only half the problem — even if they had them, $1.50 a piece seems a hell of a lot of money for an 8-bit MCU with 8K of flash in 2023.

The whole thing was made all the more frustrating by the pile of DIP8 ATtiny85s sitting on the bench, mocking me. Under normal circumstances, using them in an SAO wouldn’t really be a problem, but eight hand-soldered leads popping through the front artwork would screw up the look I had in mind.

While brooding over the situation my eyes happened to fall on one of the chips I had been fiddling with, it’s legs badly bent from repeated trips through the programmer. Suddenly it occurred to me that maybe there was a way to use the parts I already had…

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A purple PCB with many DIP chips including a 6502

Hackaday Prize 2022: Reuse Those DIP Chips To Make A 1980s-Style Single-Board Computer

May 28, 2022 by Robin Kearey 30 Comments

With the Great Chip Shortage still delaying deliveries of new components, now might be a good time to look around your lab and inspect those piles of chips that you thought “might come in handy one day”. Chances are you’ll find a good stack of 74xx series logic, once ubiquitous but today mostly obsolete thanks to powerful microcontrollers and FPGAs. It would be a shame to let them go to waste, so why not use them to make a neat 1980s-style computer?

With this idea in mind, [Anders Nielsen] designed the ABN6502: a single-board computer based on the venerable 6502 processor, but with relatively modern interfaces like a VGA monitor output, a PS/2 keyboard connector and even a wireless module to simplify firmware uploads from a PC. One design requirement was to minimize the number of new components needed; the average hacker interested in building the ABN6502 will probably have many of the chips lying around somewhere in their workshop.

The component list reads like a typical bill of materials for a 6502-based computer, but comes with a lot of flexibility to allow for part subsititution. For the CPU, both the classic NMOS 6502 as well as the modern CMOS-based 65C02 are supported, along with their 6522 companion chip that provides I/O ports and timers. A ROM socket can hold either modern, fast flash chips or traditional but slow UV-erasable EPROMs.

Instead of using DRAM chips with their complicated refresh requirements, [Anders] went for 32 KB of SRAM to implement the main memory; unaffordable in the ’80s but easily available today. Standard 74xx series logic chips glue all the components together, again with several options to add or remove features as the user prefers. Pin headers bring out the I/O ports for easy connection to external peripherals.

The ABN6502’s software library is currently limited to a bootloader, but a complete development toolchain based on the CC65 compiler should make it easy to develop all kinds of programs on this platform. We’ve already featured the clever wireless ROM flashing system, as well as a demonstration of the 6502 driving RGB LEDs.

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Parts: Chip Sockets For Dual In-line Package (DIP)

October 20, 2008 by Ian 14 Comments

DIP through-hole chips are an old package with instantly recognizable dual in-line pin rows. Beginners love these chips because they’re large and look easy to solder; we abhor them because we hate messing around with the drill. Whatever your motivation for using a through-hole chip, use a socket whenever possible. A circuit board with socketed chips is easy to test without endangering the parts, and ICs can be removed, tested, and replaced, without resorting to a soldering iron. This week, by request, we looked at several common through-hole chip sockets. Continue reading “Parts: Chip Sockets For Dual In-line Package (DIP)” →