aduc847bs8-3 Analog Devices, Inc., aduc847bs8-3 Datasheet - Page 14

• Manufacturer Part Number: aduc847bs8-3
• Description: Microconverter, 10-channel 24-bit Adc With Embedded 62kb Flash Mcu
• Manufacturer: Analog Devices, Inc.

Preliminary Technical Data
INTRODUCTION
The ADuC847 is a 12.58MIPs 8052 core upgrade to the ADuC834
and is very similar to the ADuC845. It includes additional analog
inputs for applications requiring more ADC channels as does the
ADuC845 but removes the DAC and Auxiliary ADC from the
ADuC845 specification. Otherwise it has all the same features as
the ADuC834, but the standard 12-cycle 8052 core has been
replaced with a 12.58MIPs single cycle core.
Since the ADuC847 and ADuC834 share the same feature set only
the differences between the two chips are documented here. For full
documentation on the ADuC834 please consult the datasheet
available at
GENERAL DESCRIPTION
The ADuC847 is a complete smart transducer front end,
integrating a high resolution sigma-delta ADC with flexible,
10/8-channel input multiplexing, a fast 8-bit MCU, and
program/data Flash/EE memory on a single chip.
The ADC includes flexible input multiplexing, a temperature
sensor and a PGA (allowing direct measurement of low level
signals). The ADC, with on-chip digital filtering and
programmable output data rates is intended for the measurement
of wide dynamic range, low frequency signals, such as those in
weigh scale, strain-gage, pressure transducer, or temperature
measurement applications.
The device 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 optimized single cycle 8052 offering
up to 12.58MIPs performance while maintaining the 8051
instruction set compatibility.
62 Kbytes of nonvolatile Flash/EE program memory, 4 Kbytes
of nonvolatile Flash/EE data memory, and 2304 bytes of data
RAM are 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 ADuC847 is supported by a QuickStart™
development system featuring low cost software and hardware
development tools
8052 Instruction Set
The following pages document the number of clock cycles required
for each instruction. Most instructions are executed in one or two
clock cycles resulting in 12.6MIPs peak performance when
operating at PLLCON = 00H.
Timer Operation
Timers on a standard 8052 increment by one with each machine
cycle. On the ADuC847 one machine cycle is equal to one clock
cycle hence the timers will increment at the same rate as the core
clock.
REV. PrA 05/03
http://www.analog.com/microconverter
14
ALE
The output on the ALE pin on the ADuC834 was a clock at 1/6th of
the core operating frequency. On the ADuC847 the ALE pin
operates as follows….
For a single machine cycle instruction: ALE is high for the first
half of the machine cycle and low for the second half. The ALE
output is at the core operating frequency. For a two or more
machine cycle instruction: ALE is high for the first half of the first
machine cycle and then low for the rest of the machine cycles.
External Memory Access
There is no support for external program memory access on the
ADuC847. When accessing external RAM the EWAIT register
may need to be programmed in order to give extra machine cycles
to MOVX commands. This is to account for differing external
RAM access speeds.
ADuC847