Great, it is good to have confirmation that it works for someone else! Did you try the example I posted or was it some other code you had for this display? Not that it matters for testing purposes.The HD44780 indicator has a 5 volt pin VDD supply voltage.
All other pins have TTL standard. TTL standard logical unit voltage is more than 2.4 volts.
The RP2040 has a 3.3 volt power supply and a CMOS output. Therefore, the logical unit will have a voltage of 3.3 volts at the output. Everything works for me.
No level converters are needed.
I don't know if a diode or something is recommended but I just took VBUS pin to do the backlight since it is 5V - Pin 40 on a Pico. I think stealing some VBUS 5V can work as long as the current draw is not too large.
Yes, that was my understanding as far as 3.3V CMOS high to TTL, overlap so we're good, just not vice-versa.
I just wanted to make some character display work with the parts I already had and not buy something new as well. On the other hand for other projects I do need more converters.
Some Picos may die but that is a risk I am willing to take. ;}
Statistics: Posted by breaker — Sun Jan 05, 2025 10:03 pm