512k SRAM board for your next prototyping run

Find you’re running out of memory and paying for more expensive chips just to plug this feature gap? Many of the upper offering of chips have the option of adding SRAM thanks to an on-chip hardware feature, but if you don’t have that this 512k SRAM add-on board can be used with any chip that has 13 extra I/O pins available.

That use of pins may sound crippling if you usually use low pin count chips. But thanks to a write protected state option with the memory chips, nine of those thirteen pins can serve a dual use when not reading or writing from the memory. Speaking of, the address scheme is designed to access the memory in 32-bit blocks but individual bytes are accessible too if need be. [Wardy] has been testing his design using a Propeller chip running at 75 MHz so we know it’s built for speed, but he also mentions there’s no minimum clock speed for the board to function either. He used the Open Hardware guidelines when sharing his work, and if you want one for yourself you could always give the DorkBot PDX service he used for the prototypes to get your own boards too.

[via Dangerous Prototypes]

Three digit binary clock

Here’s a three digit binary clock that [Viktor] designed. It uses a multiplexed display to drive one digit at a time with a PIC 16F628A. The video after the break shows it ticking away, display hours, minutes, and seconds in blue LEDs. You may be wondering why those LEDs are not flush to the board? [Viktor] took the project one step further than most binary clock projects, designing a PCB to fit into the enclosure of an old laptop PSU and then having the board manufactured. With options like DorkbotPDX groups orders its has become quite inexpensive to do this and it’s really good practice for when you need to design a highly complicated board for that super-fantastic project of the future.

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