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Pinguino and audio
13-05-2013, 02:35 AM,
#1
Pinguino and audio
Hey guys, I've designed a synthesizer using the Maple with an interrupt at 45kHz.

Now the Maple is a brilliant board but i'm not really using the wiring programming 'architecture' too much (I mainly just program in C nowadays, if, switch and simple math) so i'm wondering, apart from the cheaper price of the pinguino, what sort of performance are we looking at clock wise?

An single integer multiplication on the maple takes about 0.2us, where a float multiplication takes around 1.48us and a double multiplication takes about 2us. Since the pinguino is 8MHz faster, will this show a notable increase?

Some questions I have:

How easy is IO manipulation on the pinguino? I'm used to using digitalWrite and digitalRead from wiring though have also used direct port manipulation on arduino chips.

How easy is it to implement timer interrupts, the coders at leaf labs have made this easy by implementing commands linked to something called HardwareTimer where you can choose which timer you want and set up your interrupt rate etc from there.

Does the pinguino include something like systick (on arm) or micros()/millis()? Precision of timing isn't a biggy, around arduino would be alright (+/-4us)

Cheers guys! I hope to be getting a pinguino in the near future.

Harris
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13-05-2013, 08:25 AM,
#2
RE: Pinguino and audio
I'm surprised you use any floats.

I/O is fast and easy. You can use those APIs but they insert quite a delay if you need speed. The source is provided so easy to figure what inline code to use instead.

There's a hardware clock you can read that is 40MHz (on the 80MHz chips). Also milis() via software.

Only way to really be sure whether it suits you is to get one but I'd avoid the 40MHz chips - half the speed for not much less money, and very restricted memory.

John
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13-05-2013, 02:52 PM,
#3
RE: Pinguino and audio
I'm in the process of converting all effects from floats to ints. In the sampling interrupt, I only really write to PWM (around 200kHz on the maple) and have no digitalread/writes.

Either way, i've purchased one! PIC32MX440 based one.

Is there any tutorial on how to easily set up interrupts that fire at x speed?

Cheers,
Harris
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