GENERAL DESCRIPTION

The ADuC845, ADuC847, and ADuC848 are single-cycle,

12.58 MIPs, 8052 core upgrades to the ADuC834 and

ADuC836. They include additional analog inputs for

applications requiring more ADC channels.

The ADuC845, ADuC847, and ADuC848 are complete smart

transducer front ends. The family integrates high resolution

Σ-Δ ADCs with flexible, up to 10-channel, input multiplexing, a

fast 8-bit MCU, and program and data Flash/EE memory on a

single chip.

The ADuC845 includes two (primary and auxiliary) 24-bit Σ-Δ

ADCs with internal buffering and PGA on the primary ADC.

The ADuC847 includes the same primary ADC as the ADuC845

(auxiliary ADC removed). The ADuC848 is a 16-bit ADC

version of the ADuC847.

The ADCs incorporate flexible input multiplexing, a temperature

sensor (ADuC845 only), and a PGA (primary ADC only)

allowing direct measurement of low-level signals. The ADCs

include on-chip digital filtering and programmable output data

rates that are intended for measuring wide dynamic range and

low frequency signals, such as those in weigh scale, strain gage,

pressure transducer, or temperature measurement applications.

The devices operate 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 optimized single-cycle 8052 offering up to

12.58 MIPs performance while maintaining 8051 instruction set

compatibility.

The available nonvolatile Flash/EE program memory options

are 62 kbytes, 32 kbytes, and 8 kbytes. 4 kbytes of nonvolatile

Flash/EE data memory and 2304 bytes of data RAM are also

provided on-chip. The program memory can be configured as

data memory to give up to 60 kbytes of NV data memory in

data logging applications.

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. The ADuC845, ADuC847, and ADuC848

are supported by the QuickStart™ development system featuring

low cost software and hardware development tools.

FEATURES

High resolution Σ-Δ ADCs

2 independent 24-bit ADCs on the ADuC845

Single 24-bit ADC on the ADuC847 and

single 16-bit ADC on the ADuC848

Up to 10 ADC input channels on all devices

24-bit no missing codes

22-bit rms (19.5 bit p-p) effective resolution

Offset drift 10 nV/°C, gain drift 0.5 ppm/°C chop enabled

APPLICATIONS

Multichannel sensor monitoring

Industrial/environmental instrumentation

Weigh scales, pressure sensors, temperature monitoring

Portable instrumentation, battery-powered systems

Data logging, precision system monitoring