Day: December 30, 2020

Solar Flares And Radio Communications — How Precarious Are Our Electronics?

December 30, 2020 by 38 Comments

On November 8th, 2020 the Sun exploded. Well, that’s a bit dramatic (it explodes a lot) — but a particularly large sunspot named AR2781 produced a C5-class solar flare which is a medium-sized explosion even for the Sun. Flares range from A, B, C, M, and X with a zero to nine scale in each category (or even higher for giant X flares). So a C5 is just about dead center of the scale. You might not have noticed, but if you lived in Australia or around the Indian Ocean and you were using radio frequencies below 10 MHz, you would have noticed since the flare caused a 20-minute-long radio blackout at those frequencies.

According to NOAA’s Space Weather Prediction Center, the sunspot has the energy to produce M-class flares which are an order of magnitude more powerful. NOAA also has a scale for radio disruptions ranging from R1 (an M1 flare) to R5 (an X20 flare). The sunspot in question is facing Earth for the moment, so any new flares will cause more problems. That led us to ask ourselves: What if there were a major radio disruption?

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Improve ATtiny Timing Accuracy With This Clock Calibrator

December 30, 2020 by 13 Comments

The smaller ATtiny microcontrollers have a limited number of pins, and therefore rely on an internal 9.6 MHz oscillator rather than an external crystal. This oscillator lacks the accuracy of a crystal so individual chips can vary over a significant tolerance from the nominal figure. Happily the resulting timing inaccuracies can be mitigated through a calibration process, and [Stefan Wagner] has incorporated this into his Tiny Calibrator. In addition, it also has the required charge pump circuitry to reset the internal fuses to rescue “bricked” ATtinys, thus allowing those little mistakes to be salvaged.

The board has its own larger ATtiny with a crystal oscillator and an OLED screen, allowing it to measure that of the test ATtiny and generate a correction factor which it applies to the chip. This process is repeated until there is the smallest possible difference from the standard. You can find the files for the hardware on EasyEDA, and the software in a GitHub repository.

It’s important to state that the result will never be as stable as a crystal so you’d be well advised not to put too much trust in those timers, but at least they won’t be as far off the mark as when shipped. All in all this is a handy board to have at hand should you be developing for the smaller ATtiny chips.

Be careful when chasing clock accuracy — it can lead you down a rabbit hole.

Amiga Now Includes HDMI By Way Of A Raspberry Pi Daughterboard

December 30, 2020 by 34 Comments

If you had an Amiga during the 16-bit home computer era it’s possible that alongside the games and a bit of audio sampling you had selected it because of its impressive video capabilities. In its heyday the Amiga produced broadcast-quality graphics that could even be seen on more than a few TV shows from the late 1980s and early 1990s. It’s fair to say though that the world of TV has moved on since the era of Guru Meditation, and an SD video signal just won’t cut it anymore. With HDMI as today’s connectivity standard, [c0pperdragon] is here to help by way of a handy HDMI upgrade that taps into the digital signals direct from the Amiga’s Denise chip.

At first thought one might imagine that an FPGA would be involved, however instead the signals are brought out via a daughterboard to the expansion header of a Raspberry Pi Zero. Just remove the DENISE display encoder chip and pop in the board with uses a long-pinned machined DIP socket to make the connections. The Pi runs software from the RGBtoHDMI project originally created with the BBC Micro in mind, to render pixel-perfect representations of the Amiga graphics on the Pi’s HDMI output. The caveat is that it runs on the original chipset Amigas and only some models with the enhanced chipset, so it seems Amiga 600 owners are left in the cold. A very low latency is claimed, which should compare favourably with some other solutions to the same problem.

This isn’t the first time we’ve seen an HDMI Amiga conversion, but it’s one that’s usable on more than simply the big-box machines.

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