Spin Semiconductor

I know this is rather belated, but I've also just received some chips from AliExpress (2008 ones, it appears) - and got exactly the same result as nacho-conso. I live in Australia and the only supplier I've a quote from was Profusion who charge US$49 for shipping. So AE seemed to be worth a try. Ah ...

The problem is to synthesize a triangle or sawtooth waveform of constant amplitude from a variable-pitch incoming square wave. The ramp can be generated by incrementing or decrementing a register, resetting it at transitions. The pitch can be measured by counting the number of processor clocks betwe...