The Tiny Tapeout custom ASIC project has been around for a while now, and has passed through several iterations of its production. On each Tiny Tapeout chip are multiple designs, each representing an individual project, and in use the chip is configured to present that project to its pins. Given enough Tiny Tapeout chips it was inevitable that someone whould eventually make a project using two such functions, and here’s [Sylvain Munaut] with an SDR using Tiny Tapeouts 6 and 7.

At its heart is [Carsten Wulff]’s 8 bit ADC from Tiny Tapeout 6, fed by [Kolos Koblász]’s Gilbert cell RF mixer from Tiny Tapeout 7. There’s a local oscillator provided by an RP2040, and a USB interface board which sends the data to a host computer where GNU Radio does the maths. On the bench it’s receiving an FM signal generated around 30MHz by a signal generator, followed by some slightly indistinct commercial radio stations.

It’s clear that there are many better SDRs than this one, and that (as yet) Tiny Tapeout is perhaps not the radio enthusiast’s choice. But it does demonstrate beautifully how the chips are more than just curios, and we’re definitely in the era of useful on-demand ASICs.

The video is below the break, meanwhile you can learn about Tiny Tapeout from [Matt Venn]’s Supercon talk.

Making a physical doughnut is easy enough, given a good dough recipe and a nice hot deep fat fryer. But have you ever considered making a one in physical electronic hardware, on an ASIC? [A1k0n] has, at least in terms of making a virtual doughnut. It’s a hardware implementation of a ray tracer which renders a rotating doughnut to a VGA screen, and it comes courtesy of around 7000 logic cells on the latest iteration of Tiny Tapeout.

We will not pretend to be mathematical or ray tracing experts here at Hackaday so we won’t presume to explain in detail the circuitry, suffice to say that the clever hack here lies in a method using only shift and add operations rather than the complex trigonometry we might expect. It uses a slightly esoteric VGA mode to work with the device clock, so while CRT monitors have no problems it can have artifacts on an LCD. The full explanation goes into great detail, for the math heads among you.

We’ve reported on quite a few Tiny Tapeout projects over the years, as the many-ASICs-on-a-chip extends its capabilities.