Can I make a suggestion for a possible rev B of this module?
Why not put a jumper (or even a solder link if you’re worried about noobs) that allows the selection of either 3v3 or 5V for the supply rail for the chip?
The IO pins are 5V capable if the device is powered from 5V. The STM32F4 devices that GHI use in the open source Gadgeteer boards have 5V tolerant pins on almost all the I/O pins (actually, I think is is all of them).
Phil
Not needed. The supply rails (I assume you’re talking about the ones below the PWM pins) are whatever you supply at the V+ pin.
EDIT: After taking another look I think you may be talking about the lack of a 3V3 supply rail on the module. I agree that would be nice. I’m wondering if that was done intentionally though so that the on-module chip is not starved of current.
Not sure what you mean here. The IO60P16 pins are 5V tolerant.
If you mix 3.3V and 5v you can get trouble with I2C bus. Using software i2c may be not an issue if stm32 is tolerant. In this case need open drain on stm32 side and resistor on 5v.
Not a bad suggestion but Gadgeteer is designed so beginners/students will not damage the system accidentally, especially the mainboard. Having a 5V option can make this very risky as not all mainboards are 5V tolerant.
The future is 3.3V (and lower) so 5V should die off at some point.
I’m confused… So, why does the IO60P16 only have 5V then?
WRONG on both comments. I am saying that it would be nice to be able to power the CY chip from the 5V on the Gadgeteer cable as an option.
THE IO60P16 PINS ARE NOT 5V TOLERANT. Ian, you need to read (or understand?) the device datasheet before making statements like this. The CY chip on this module is powered from 3.3V - ie VDD= 3.3V. The datasheet clearly states that the absolute maximum input voltage on any pin is VDD + 0.5V = 3.8V in this case. That’s WHY I was suggesting it would be nice to have the option.
I’ve hacked it anyway, but because of the board layout you have to slice up the gadgeteer cable (or else use it on the Cerbuino Bee with a custom cable to the Arduino digital connector 1).
Not tolerant and there is a note about this on catalog I believe.
The 5v on the board is to optionally power servos and not to get 5v on the pins.
OzFlip, I appologize. Understanding is definitely the issue. I’ve spent countless hours reading that datasheet in the past month & a half mostly from the point of view of the commands while developing the driver. I was referring to the Vih notes that listed a range of 3.0V to 5.5V. I see the error in my understanding now. Thank you for the education.
Add logic level converters as standard equipment…