The LS7366 CMOS high-speed up/down counter features an SPI interface for peripheral communication. Each of the counter’s functional modes is configured with two read/write control registers. Operating over a voltage range of 3 to 5.5 V, the unit features count modes such as non-quadrature, quadrature, free-running, single-cycle, modulo-N, and range-limit. The LS7366 can be programmed to function as a true 1-byte, 2-byte, 3-byte, or 4-byte counter. In these cases, the carry, borrow, and sign flags generated would be based on the selected byte configuration and not on the entire 32-bit field. The counter can communicate with the host controller over four wires via the SPI interface. This is compared with the 11 wires required for parallel interfaces, such as the manufacturer’s LS7166. The open-drain latched/unlatched FLAG output of the LS7366 allows multiple counters to interrupt the host controller over a single wire-OR’d interrupt line. Providing a count frequency of 40 mHz at 5 V, the counter is available in 14-Pin DIP, SOIC, and TSSOP packages. The LS7366 is priced at $1.85 in quantities of 1,000, and is typically available from stock within four weeks.