VSDSP Forum

The pull-down is about 1Mohm and you can see them from pin table. DIOPD type pin is with and DIO without pull-down. Normally those pins without pull-down don't use more current but if those pins are left to floating or some other chip has pull-ups and then those pins are biased somewhere around IOV...

Just some random thoughts which have popped up to my head from this thread and can be totally irrelevant to your design: If VBUS is connected to VHIGH, you can read it with SAR. If VHIGH is measured, it is possible then to check how the data pins are and after that start USB device program. If ther...

If you can spare one GPIO, you can perform attach and detach detection from VBUS, like it should be done and do without the 1M pull-ups. My charging scheme will require detection of Vbus, so I will be using a GPIO for that already. I read elsewhere that it is suggested to use D+/D- connection detec...

As always, thanks for the responses Hannu and Pasi! Your help has been instrumental in helping move this project forward. I am also on uncharted waters and I'll try to get you a better answer, but USB_UTMIW register is the one register to poke. Ok. I wasn't sure if there were additional registers th...

I have some new questions, but they are still relevant to this thread, so I will ask them here: I need to implement USB Dedicated Charging Port (DCP) detection, as outlined in the USB battery charging specification. I don't want to increase my BOM unnecessarily, especially if there is the possibilit...

Once again, your responses are greatly appreciated, Hannu. I believe I have found some errors in my thinking. I won't concern myself with the 159 kHz filter and I will leave it as-is for now. I was trying to accomplish all my needs with a single IC dual op-amp (1/2 for preamp, 1/2 for bias voltage b...

I'm back with some fresh new questions! The BOB and Dev Board have similar line-in circuits, so I want to know what the significance of some of the components are. First, there is the 100k resistor to ground. The VS1005 datasheet states an input impedance of 100k for the mic/line inputs. Does this r...

Thank you for the information, Hannu. I will add a capacitor and bleed resistor among other things to the PWRBTN circuit to make it more similar to the developer board. I figured GPIO protection diodes might get forward biased and start conducting in such a situation, but I didn't think it would cau...

Thank you for the quick response, Hannu! I will do as you say regarding the regulators/power inputs. I will also keep an eye on AVDD and attempt to keep the rail noise-free. Thanks for the schematic! When you say "Calculate the driver so that there is something like 3V." do you mean to cal...

Hello! I am happy to say that my project is moving forwards in a sensible direction after taking too many detours, and am in the process of designing my PCB. I'm basing the foundation on the VS1005 Breakout Board v2.1 schematic, and have some questions regarding things I can omit: First off, I will ...