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PostPosted: Wed Aug 08, 2012 12:20 pm
by carbon14
WiringPi is the library that I thought I would start with to use the GPIO interface. It's designed to be familiar to Arduino users. I'm not one of those, but that doesn't make it a difficult interface for anyone else. It's clean and simple, and has a great little command line tool which is a great confidence builder when you start.

I'll let you know how I get on.

Re: WiringPi

PostPosted: Wed Aug 15, 2012 8:30 am
by carbon14
Well it's a very nice library, and seems very fast.

I'd like to interface to a yamaha YM3812 which claims to have a minimum clock speed. I can well imagine that the internal registers in the chip are dynamic charge based devices, so a minimum clock speed may be genuine and I think that I can just about reach that speed with wiringPi.

If it falls short, I'll just have to add a crystal for the clock and use the Pi to generate the remaining signals which would seem eminently feasible. Generating the clock through the Pi would give me an enormous degree of control and accuracy in my research.

Took me longer to remember the correct syntax for linking the executable than it did to start writing useful programs last night. Very pleased with it.

Re: WiringPi

PostPosted: Mon Aug 20, 2012 10:45 am
by carbon14
I've been talking to a Yamaha YM3812 chip using wiring Pi.

The chip is a CMOS chip with TTL compatible i/o, so I am just driving it's inputs directly from the 3.3 volt r-pi output. This should be well within the input tolerances of TTL.

The chip outputs are 5 volts, so I'm using a resistor divider to drive just under 3.3 volts into the r-pi inputs. So far it seems to be working fine.