2016-02-17 02:48 AM
Hi,
I'm second year student at UTP in Poland. I have to do project based on STM32F407VG. It's just simply communication with keyboard. But I have problem - power on my keyboard. I read that to power PS/2 I have to get 5V and max. 300mA. What i research that 5V output power its ok for my STM. But, I still dont have respone from keyboard. Can someone help me solve this? #keyboard #stm32f4 #ps/22016-02-17 03:17 AM
Many of the GPIO pins on the STM32F407 are 5V-tolerant; double-check in the user manual that the pins that you’re using are 5V tolerant.
“5V tolerant� means that a pin can safely read a 5V digital signal without burning out, but they can’t transmit at 5V and many keyboards may not respond to 3.3V signals.
You will need a level translator to convert the 3.3V logic out of the STM32 into 5V logic signals.
There are many ways to do this, including transistors, an op-amp, or a purpose-built level translator IC.
If I recall correctly, the data line is bidirectional so you will also need to deal with that.
2016-02-17 06:00 AM
Diagram the pins and connections used. Show the code you are using to read and clock the keyboard.
2016-02-17 01:12 PM
Hi, thanks for reply :) I figured out and I get power to keyboard by 5V pin, I check this and its 4.8V. But I have problem with pressing button on keyboard. If I do that, clock line is not falling. Here is code:
Thank's guys for support me !