[sdiy] Tap Tempo LFO

[Amos]

When you said "general purpose mcu" I thought "8051" of which there
are several that could generate a satisfactory clock signal with very
little external circuitry, I think.

On 12/9/09, Eric Brombaugh <ebrombaugh1 at cox.net> wrote:
>
> On Dec 9, 2009, at 5:18 AM, Antti Huovilainen wrote:
>
>> On Tue, 8 Dec 2009, Eric Brombaugh wrote:
>>
>>> Using a general-purpose MCU to create a clock for a BBD is probably out
>>> of the question for most garden-variety processors. While a lot of them
>>> have divider-based timing generators built-in, the high-frequency
>>> resolution is probably not adequate to support decent timing & frequency
>>> control at the rates needed to clock a BBD.
>>
>> Here I disagree. A simple VCO is not that hard to do if you stick to V/Hz
>> and disregard linearity. A PLL would also be dead simple to do, too.
>>
>> With the VCO you need to build a calibration table and/or adjust the
>> frequency on the fly, but that's hardly rocket science.
>
> Perhaps I need to defend the statement above with a little more detail:
>
> * 'general purpose MCU' means an inexpensive processor with a normal
> complement of peripherals like low-res ADCs, timers, GPIO, etc. Think a PIC
> or AVR.
>
> * I thought the OP was talking about creating a BBD clock source without
> using any other external components - that was my assumption in this first
> paragraph. Further on I discussed the possibility of adding an external PLL
> or programmable oscillator.
>
> So I believe we agree - with a simple external oscillator and minimal
> control it would be possible to create a clock for a BBD using a cheap MCU.
>
> Eric
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