Hi RT! I had a few questions about CV ins and outs in your very exciting new products. (About to start playing with CV outs on my new Wizard, and I wanted to get oriented first).
I am very much on the software side of things, so please forgive any hardware-based misunderstandings in the below!
In a comment to Paul Pichon on your Kickstarter, Martin wrote:
CV levels: -10v to +10v! There will be options to select unipolar or bipolar function per connection from the patch. This means that the resolution of the converter is not wasted where it’s not needed, such as the negative half with unipolar envelopes.
Looking at your code, I am wondering if this applies only to the Magus, since it seems like it’s functionality associated with the MAX11300.
Moreover, I’m wondering if there is simultaneous -10 to 10 range, as the input and output options don’t seem fully comprehensive (based on the hardware docs and the constants defined in
MAX11300.h, which are used in
Owl.h] when calling
updateMAX11300 in the
loop()). In particular, output seems to get only 0 to 10, -5 to 5, and -10 to 0: so no unipolar 0-5 (meaning that it’s really an 11-bit DAC for some applications, and may need to be limited besides) and also no bipolar -10 to 10 (which is the full Eurorack range, right?) Input gets those options plus 0 to 2.5.
Right now, it looks like
setPortMode only supports
PCR_Range_DAC_0_P10, so 0-10) and
PCR_Range_ADC_0_P10, so 0-10) but that is probably just preliminary–I appreciate that the Magus hasn’t even been released yet
Is this right, or are you doing voltage manipulation post-MAX11300 to change up the options? It’s too bad there’s no 12-bit 0 to 5V option, which is a very common range for some hardware (almost all guitar pedals controllable by CV, for example). The loss of resolution is less concerning than the possibility of accidentally going out of range, which (especially in the negative) can do a number on non-Eurorack CV hardware…
As to the Wizard side, I’m more confused. As to the outputs, it looks as though the two CV DACs are just using the STM32F4 outputs, which I think only from 0 to V_REF (max 3.6V for that chip?) The gate looks like it uses GPIO, so I’m also not sure there. And I haven’t been able to find anything on the inputs, especially regarding whether they’re bipolar.
I know it’s early days for this hardware but any light you could shed on the above would be appreciated, as I’m trying to figure out if a Wizard or Wizard/Magus setup is going to meet my CV needs. Many, many thanks!