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SiriusHardware · 31st Oct 2021, 12:06 am

I think the capacitor charge / discharge principle is the way a lot of the analogue stick interfaces worked at the time, possibly even the then standard PC analogue 'Game' port worked that way, I'm not sure.

I did also consider voltage to frequency / resistance to frequency converters or variable one-shot length (send a pulse, wait to see how long it comes back) using 7212x monostables, but the problem with those methods is they don't really produce a linear range of output values corresponding to the control resistance, so you probably end up having to have a look-up table to compensate.

So my inherent laziness kicked in and took me back to something which will give me a nice linear 6-bit position value in one easy (and instant) parallel read. The 'historically nice' way to do that would be using two ZN448s or one ZN448 and a 4051 switching one of two pot wipers onto the analogue input of the ADC. From the point of view of making something which other people can easily follow / reproduce I like the idea of using a PIC with at least two analogue inputs and 6-bit parallel output rather better.

I don't think we should get too hung up on the use of a microcontroller to emulate old school peripheral / interface ICs, after all, Ortonview uses a PIC family device which didn't exist when the MK14 was originally around.

31st Oct 2021, 12:06 am	#118
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,553	Re: MK14 Programming Interface I think the capacitor charge / discharge principle is the way a lot of the analogue stick interfaces worked at the time, possibly even the then standard PC analogue 'Game' port worked that way, I'm not sure. I did also consider voltage to frequency / resistance to frequency converters or variable one-shot length (send a pulse, wait to see how long it comes back) using 7212x monostables, but the problem with those methods is they don't really produce a linear range of output values corresponding to the control resistance, so you probably end up having to have a look-up table to compensate. So my inherent laziness kicked in and took me back to something which will give me a nice linear 6-bit position value in one easy (and instant) parallel read. The 'historically nice' way to do that would be using two ZN448s or one ZN448 and a 4051 switching one of two pot wipers onto the analogue input of the ADC. From the point of view of making something which other people can easily follow / reproduce I like the idea of using a PIC with at least two analogue inputs and 6-bit parallel output rather better. I don't think we should get too hung up on the use of a microcontroller to emulate old school peripheral / interface ICs, after all, Ortonview uses a PIC family device which didn't exist when the MK14 was originally around.