Monthly Archives: October 2020

The long road to QL-VGA v2

As mentioned last time, I’ve designed a new QL-VGA version that is a lot more complex than the simple “hat” I designed for v1, but will hopefully be a lot easier to manufacture.

I’ve ordered the board early September and they arrived a few days later. Unfortunately JLCPCB, my go-to prototype house, while having an incredibly good cost/value ratio, can only populate parts they have in stock and at that date the FPGA was not available. Damn, but OK, I let them make the boards without the chip and at the same time ordered some from their sister company LCSC as you get a shipping discount when you’re ordering a board at the same time.

The boards arrived fine. The chips arrived in Germany, too, but then DHL somehow lost them. For some time I was still hoping that they will turn up, but as of today, one month later, they are still lost. In China the FPGAs are affordable, about 4€ each, but shipping usually takes a long time or is rather costly. Outside of Chine the chips are a lot more expensive, with a price range of 15 to 50€(!), and initially I didn’t really want to spend that much on an unproven board that of all incompetent people I mostly designed myself!

A few days later I found one chip in Spain, just 5€ plus 2€ shipping, hurray! Bought it immediately. Two days later the guy wrote “sorry, I have to cancel the sale, I don’t find the chip anymore!”. What the…?

OK, I give up, I order some more in China and just wait it out. Found some good offer on AliExpress and… that was 10 days ago and they haven’t even shipped them yet! What the…? Damn, before I’m getting completely cranky I gave up once again and ordered some from Mouser in the US, at 15€ apiece, but at least they arrived this morning, only 4 days later!

Oh joy, one month after I got the boards I finally have a chip to go with it! So, quickly solder it in, program the power supply to 5V/100mA and… hm, current regulation kicks in. OK, one short burst with 200mA in case 100 is not enough… nope, likewise. Damn, apparently there is something seriously wrong with my beautiful board! 🙁 After some head scratching I checked the chips against the CAD data and what’s that? One chip is soldered in 180 degree rotated! Quickly check the order but no, I specified it correctly, so while I am usually very happy with JLCPCB this time they screwed up.

Fortunately this is just an SPI EEPROM with lowly 8 pins, so easily fixed. And then… it works! It fucking works! First time! My most complex board ever just works! This is a kind of happiness most people probably cannot comprehend but I was literally jumping through the house, fighting the air with my fists.

So, at long last, here it is:

QL-VGA v2 first prototype

So, what now? Well, first a lot more testing of course and eventually find a board house that can manufacture it in greater numbers. With all chips on it, preferably oriented correctly! Hopefully this will work out OK, too, as it will be another first for me…