TinyRTC

I now have a scheme program that sets and gets the time from a TinyRTC connected to the STM32F4 discovery board. It's actually fairly neat. See examples/stm32f4-discovery-flash.scm and tinyrtc.scm. I couldn't get it to work for ages, because I'd forgotten I needed to configure the pins in open drain mode, as well as configuring I2C mode. I'll have to go back and hack on the generated use-pin code so it does that automatically. That's pretty exciting though. Using map to convert lists from binary to BCD is a neat demonstration of the relevance of scheme, as is the fact that I'll eventually be able to automate pin configuration with some simple rules.

Popular posts from this blog

Update on drilling holes in aluminium

I really should have written this post long ago, since my first attempt at having a working drill stand fell well short of satisfactory. In fact I'm bemused to find the post doesn't already exist. Clearly all the ranting was only in my head... The drill press proved woeful. Actually, I wrote a review on Amazon, so I guess that's what I'm remembering. A lot of people thought oh well, it's cheap what do you expect. I went and bought a Record Power DS-19 for £59. Yes that's twice as expensive, but it's twice bugger all, and using it is a completely different experience. In my previous post it wasn't up to the challenge of using an end mill. Nothing else has proved beyond it. I also didn't end up with the drill. I bought it, and returned it, after I found the chuck was more than 43mm, and so the drill wouldn't go in the stand, even though it had a suitable collar. Instead, I got a  Makita DP4011 . This cost £120. I actually have no idea why I di...
Read more

Embedded Rust

I want to become fluent in Rust, and I have a few things I'd like to do with embedded systems, so I figured I'd combine the two. This has got a lot easier since I first thought about it: there's a book . The thing I specifically want to do is regularly sample the ADC, using non-blocking APIs. This is sort of supported: There are some standardised HAL API s, and they use nb  which is a generalised non-blocking mechanism. This does mean, however, that you end up needing a spin loop that tries everything you are waiting for. You can handle interrupts, so perhaps there's a sleep function that wakes up after an interrupt has been processed? Then I could add something like Chibios events: the interrupt would set the right event flag, and the main loop would act on each event flag that was set, each time it woke up. I don't need to do this, because the RTFM framework does it already, and statically analyses your program for deadlocks. RTFM lets you define '...
Read more

Acrylic aquarium goodness

Image
I got my acrylic tank on Monday. theplasticpeople.co.uk deserve a link, because it looks great, and they were very helpful. It wasn't cheap, but it was still cheaper than the low iron glass. It looks even better. You would think that 10mm of acrylic would look a bit chunky, but it just doesn't. Perhaps its the clarity. The corners look perfect, basically because they are. It now seems really silly I was so determined to have rounded corners. I may eventually find it scratches easily, but for now I'm going to enjoy it. I've done some aqua-scaping and put the plants in. They are mostly unscathed. I got 5 bunches of Egeria densa with a bulk discount, and they do look a little worse for wear. It was hardest to ensure good light for them. I bought most of my plants from www.gardenandleisure.com . Its certainly the cheapest place to buy the Tropica range of plants, and they did a good job of the packaging. I've now found www.plantedtanks.co.uk who have an amazing ra...
Read more