ADuC834

The ADuC834 is a complete smart transducer front-end, integrating two high-resolution sigma delta ADCs, an 8-bit MCU, and program/data Flash/EE Memory on a single chip.

The two independent ADCs (Primary and Auxiliary) include a temperature sensor and a PGA (allowing direct measurement of low-level signals). The ADuC834 ADCs with on-chip digital filtering and programmable output data rates are intended for the measurement of wide dynamic range, low frequency signals, such as those in weigh scale, strain-gauge, pressure transducer, or temperature measurement applications.

The ADuC834 operates from a 32 kHz crystal with an on-chip PLL generating a high-frequency clock of 12.58 MHz. This clock is, routed through a programmable clock divider from which the MCU core clock operating frequency is generated. The microcontroller core is an 8052 and therefore 8051 instruction set compatible with 12 core clock periods per machine cycle.

62 Kbytes of nonvolatile Flash/EE program memory are provided on-chip. 4 Kbytes of nonvolatile Flash/EE data memory, 256 bytes RAM and 2 KBytes of extended RAM are also integrated on-chip. The program memory can be configured as data memory in datalogging applications.

The ADuC834 also incorporates additional analog functionality with a 12-bit DAC, dual current sources, power supply monitor, and a bandgap reference. On-chip digital peripherals include two 16-bit DACs/PWM, watchdog timer, real time clock (time interval counter), four timers/counters, and two serial I/O ports (UART and SPI).

On-chip factory firmware supports in-circuit serial download (via UART), as well as single-pin emulation mode via the EA pin. A functional block diagram of the ADuC834 is shown above with a more detailed block diagram shown in figure 11 (page 18).

The part operates from a 3V or a 5V supply. When operating from 3V the power dissipation for the part is below 10mW. The ADuC834 is housed in a 52-lead MQFP package.