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