Electric Dollar Store

DIG2 can be used it for indicators and readouts. It can be set to one of four I²C adresses, so multiple units can be used to make a display of up to 8 digits. The display is bright and flicker free. The brightness is software-controlled, and is gamma-corrected for a smooth increase over the entire 1-255 value range. DIG2 has a straightforward write-only protocol, with several commands for setting the display. The raw command sets all 16 segments:

0x00
<dig0>
<dig1>

The hex command displays a hex byte value 0x00-0xff:

0x01
<value>

The dec command displays a hex byte value 0-99:

0x02
<value>

The brightness command sets the brightness from 0x00 (completely dark) to 0xff (full brightness):

0x04
<bright>

import sys
import serial
import time

from i2cdriver import I2CDriver, EDS

if __name__ == '__main__':
    i2 = I2CDriver(sys.argv[1])

    d = EDS.Dig2(i2)
    for i in range(100):
        d.dec(i)
        time.sleep(.05)

#include <Wire.h>

void dig2_show(byte v, int m = DEC)
{
  Wire.beginTransmission(0x14);
  Wire.write((m == HEX) ? 1 : 2);
  Wire.write(v);
  Wire.endTransmission();
}

void setup() {
  Wire.begin();
}

int i;
void loop() {
  dig2_show(i++);
  delay(100);
}

from machine import I2C
import time

class Dig2:
    """ DIG2 is a 2-digit 7-segment LED display """

    def __init__(self, i2, a = 0x14):
        self.i2 = i2
        self.a = a

    def raw(self, b0, b1):
        """ Set all 8 segments from the bytes b0 and b1 """ 
        self.i2.writeto(self.a, bytes((0, b0, b1)))

    def hex(self, b):
        """ Display a hex number 0-0xff """
        self.i2.writeto(self.a, bytes((1, b)))

    def dec(self, b):
        """ Display a decimal number 00-99 """
        self.i2.writeto(self.a, bytes((2, b)))

    def dp(self, p0, p1):
        """ Set the state the decimal point indicators """
        self.i2.writeto(self.a, bytes((3, (p1 << 1) | p0)))

    def brightness(self, b):
        """ Set the brightness from 0 (off) to 255 (maximum) """
        self.i2.writeto(self.a, bytes((4, b)))

def main():
    i2 = I2C(1, freq = 100000)

    d = Dig2(i2)
    for i in range(100):
        d.dec(i)
        time.sleep(.05)
Default I²C address 0x14 (0b0010100)
Current consumption (typ.) 25 mA
Vcc 3.3 V