Demonstration circuit DC2343A is a complete system level solution for a nanopower buck-boost DC/DC with integrated coulomb counter. The DC2343A contains a PIC16F1459 embedded processor for communication to the PC over USB and the LTC3335 via its I2C port. The GUI is capable of reading and writing all the control registers on the LTC3335 as well as displaying and resetting all its alarm registers. The firmware and software for the embedded system and the GUI are available at the LTC3335 solutions page. The DC2343A uses two analog-to-digital converter channels to sample the battery and output voltages. The voltage samples improve the functionality of the GUI, and allow optimal software correction to the measured coulombs. By adding the software correction the first order known errors are compensated for over the operating range and the resultant coulomb count is accurate to within 3%.