With a TFT LCD, where would the "RS/DC" pin go?

Hardware
1

I bought a cheap chinese LCD that someone has already gotten working with an Arduino (even though it’s a 3.3v board), and I figured I’d get it working with my Photon. The guy has already made a code library for it here:

With this included wiring guide here:

TFT side   -------------------- microprocessor  
- Vcc       -->     +3V3V(!!!!)
- Gnd       -->     Gnd
- CS        -->     CS pin (3v3 level!)
- RST       -->     connect to a MCU pin or tie to +3V3 or 10K to 3V3 (do NOT leave float!)
- A0        -->     DC or RS pin (3v3 level!)
- SDA       -->     Mosi (3v3 level!)
- SCK       -->     Sclk (3v3 level!)
- LED       -->     Some display need a resistor (see note below)

Now VCC and GND are self explanatory. “CS” I connected to the “SS” pin (the A2 pin on the Photon) since the internet seems to indicate those are the same thing, like how CLK and SCK are the same thing. I did what they said for RST. But I’m not sure what to do with “A0” on the LCD. Guide says to hook it up to “DC or RS pin”, but I don’t have anything with those labels on my Photon pinout. Any ideas where they’d connect? I’ll probably be back for help later porting his library over to work on the Photon :wink:

2

@moeburn, DC/RS can be any pin since it is usually specified in the display object’s constructor (in your code). The LED is what will draw the most current is hooking it up to 5V is most likely fine but you will need a current limiting resistor. You could start with limiting the current to 20ma using a 240 ohm resistor. If that is not bright enough, you can use a 120 ohm resistor (42ma). :smile:

3 Likes
3

Thank you!