The TSS400 Standard ( TSS400-S1) sensor signal processor is an ultra-low power, intelligent, 12-bit A / D converter ( ADC) that has been preprogrammed with the Sensor Macro Programming Language ( SMPLTM ) interpreter. This language allows fast, easy, and economical customization of the TSS400-S1 to a wide range of sensor signal processing applications. The application specific programs that customize the operation of the TSS400-S1 are stored in external EEPROMs along with any additional data required by the application. The main components of the TSS400-S1 are a four-input multiplexed 12-bit ADC, a programmable constant current source, an LCD driver capable of driving 56 segments using a 4-MUX drive scheme, two crystal controlled independent timers, an on-board RAM, six output-only pins ( R1 to R6 ), a 4-bit programmable I / O port ( K1, K2, K4, K8 ), and I2C serial EEPROM communications. Operation of the TSS400-S1 is very adaptive because it is controlled by a SMPL language program. These programs can be stored in an external EEPROM (standalone mode) or stored in a host computer ( slave mode ). The SMPL language is a powerful, easy to learn, and easy to use macro language. Some of the SMPL language features are single-command EEPROM read and EEPROM write operations, three levels of subroutines, a single-command A / D conversion instruction that specifies the number of conversions and the type of conversion (either compensated or noncompensated) to be made, and two reduced power consumption modes ( DONE and OFF ).