Do I need to use any Resistors for VGA pins?

RoCorbera / BlueVGA

VGA library for STM32F103C (BluePill) that can manipulate a screen with 28x30 tiles with 8x8 pixels each, in a total resolution of 224x240 pixels with 8 colors using a very low footprint

Other

61 stars 11 forks source link

Do I need to use any Resistors for VGA pins? #1

Open souravg009 opened 4 years ago

souravg009 commented 4 years ago

Hi I was going through your project and in the stm32duino thread, (https://stm32duinoforum.com/forum/viewtopic_f_2_t_3318.html). Amazing work! Just out of curiocity, are any resistors required between R,G,B pins of VGA and STM32 mcu? Other 'works' with VGA have several "potential divider" resistors of 220 Ohm as the pins MAX input voltage is ~1V. I am about to walk on your path, so I thought, its better to ask you before damaging something. :innocent:

RoCorbera commented 4 years ago

Hi, Actually the thread for this project is at https://www.stm32duino.com/viewtopic.php?f=10&t=347&sid=4dd9fdf3c73c07ed2ba396bda4120798

You can use a 330 ohms resistor like this: STM32 pin ---> 330 ohms ---> connection to VGA pin.

Doing so when STM32 pin is high, the voltage will drop from 3.3V to 0.6V.

When using modern LCD VGA monitors, I use to connect STM32 directly to VGA and I never had any issues... But to be safer just use a 330 ohms resistor as I wrote.

I hope it works fine for you!

RoCorbera commented 4 years ago

Closing it, as this is not an issue related to the library code.

RoCorbera commented 3 years ago

Keeping this issue open for consulting similar questions.