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11 years, 3 months ago.
LCD display CFAH1602B-YYH-JT with mbed NXP LPC1768 wiring connection
Hello community,
I'm trying to connect a Crystalfontz LCD display CFAH1602B-YYH-JT with mbed NXP LPC1768 but i'm having some difficulties to understand the wiring datasheet information for 3.3v connection.
Vss and Vdd apparently are clear to me but Vo (LCD PIN 3) isn't, does anyone tried to connect this lcd to mbed?
Best Regards, Hugo Rodrigues
1 Answer
11 years, 3 months ago.
Vo is the contrast voltage. If you use 3.3V to supply Vdd, this voltage has to be negativ to gnd ! See page 28 of the datasheet. There is a circuit on page 29 of the datasheet to use a pwm signal and two schottky diodes to make a negativ voltage. You can try this. To see if your display is working on the mbed, use a battery and a 10K poti to make this signal negativ.
Pin 3 is normally used for adjusting the lcd contrast. Connect to a potmeter wiper. The voltage should typically be adjustable between powersupply voltage and gnd. Some displays need a small negative lcd contrast voltage, especially when using 3V3 power supply or at low temperatures. You could try running the display at 5V powersupply and use a small positive lcd contrastvoltage. That should work with mbed.
posted by Wim Huiskamp 25 Jan 2013