MAX7221, very easy to write to with SPI
Can control from 3 to 8 seven segment displays.
1 resistor sets max current, 16 levels selectable via software.
Request a sample, or purchase for $4.
Easy to wire up to common cathode 7-segment displays.
All segments wired in parallel, unique common cathode to each device.
Writing to its registers:
// MAX7221: write shutdown register
digitalWrite(SS,LOW); // take the SS pin low to select the chip:
SPI.transfer(SHUTDOWN_ADDRESS); // select the Address,
SPI.transfer(0x00); // select the data, 0x00 = Outputs turned off
digitalWrite(SS,HIGH); // take the SS pin high to de-select the chip: