[SOLVED] 74AHCT125 - Quad Level-Shifter (3V to 5V) - 74AHCT1

[stantiques]

I'm new. I want to know how to wire this https://www.adafruit.com/product/1787 to this https://www.adafruit.com/products/420 ?

A little back story. I used this guide https://learn.adafruit.com/connecting-a ... i/overview and got the led matrix working pretty good but there is some 'static' or 'artifacts'. In the article it has this note "These panels are designed to take 5V logic, and the Pi uses 3.3V logic. For some panels, the 3V logic is not high enough to trigger. If you're having difficulty you may need to use level shifting chips such as https://www.adafruit.com/product/1787 to shift the 3.3V up to 5V!".

So I want to order the level shifting chip but I don't really understand how it is wired together. Any help would be greatly appreciated and have a great day!

[adafruit_support_mike]

The 74AHCT125 is a quad buffer with tristate output. Each functional unit in the chip has three pins:

- A (logic-speak for IN)
- Y (logic-speak for OUT)
- /OE (Output Enable)

Connect an output from your RasPi to the A pin. As the GPIO goes high and low in the 0v-3.3v range, the Y pin will match it in the 0v-5v range.

The /OE pin controls whether anything happens on the Y pin. If /OE is high (3.3v or 5v), the Y pin will go into 'hi-z mode'.. its resistance goes up to about 10M, more or less disconnecting it from the rest of the circuit. If /OE is low, the Y pin goes back to providing high and low voltages and being able to handle about 8mA either way.

For your purposes, connect /OE to GND and forget about it. Connect the VCC pin to 5v then connect a signal from the RasPi to A and the LED matrix to the corresponding Y.

Each chip will level-shift 4 signals, and every signal will be a copy of that same arrangement.

[stantiques]

Perfect! Thanks!