Additionally, there are up to 160 general purpose I/O lines on the LPC2300 and LPC2400. The GPIO can toggle at rates up to 36 MHz to interface with a variety of CPLD, FPGA, and other external devices. Finally, there is an on-chip regulator that requires only a single 3.3 V power supply for both the I/O and the 1.8 V required for the ARM7 core.