ADuC824

The ADuC824 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. This low power device accepts low-level signals directly from a transducer.

The two independent ADCs (Primary and Auxiliary) include a temperature sensor and a PGA (allowing direct measurement of low-level signals). The ADuC824 ADCs with on-chip digital filtering 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 ADC output data rates are programmable and the ADC output resolution will vary with the programmed gain and output rate.

TheADuC824 operates from a 32 kHz crystal with an on-chip PLL generating a high-frequency clock of 12.58 MHz. This clock is, in turn, 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-instructionset- compatible. The microcontroller core machine cycle consists of 12 core clock periods of the selected core operating frequency. 8 Kbytes of nonvolatile Flash/EE program memory are provided on-chip. 640 bytes of nonvolatile Flash/EE data memory and 256 bytes RAM are also integrated on-chip.

The ADuC824 also incorporates additional analog functionality with a 12-bit DAC, current sources, power supply monitor, and a bandgap reference. On-chip digital peripherals include a watchdog timer, time interval counter, three timers/counters, and three serial I/O ports (SPI, UART, and I2C-compatible). On-chip factory firmware supports in-circuit serial download and debug modes (via UART), as well as single-pin emulation mode via the EA pin. A functional block diagram of the ADuC824 is shown above with a more detailed block diagram shown in Figure 12.