AS8218 / AS8228
Highly Integrated Single Phase 2-Current Energy
Metering Integrated Circuits with Microcontroller, RTC,
Programmable Multi-Purpose I/Os and LCD Driver
DATA SHEET
1. Key Features
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Precision single-phase, one or two current input
energy measurement front-end including Sigma-
Delta modulators for A/D-conversion and digital
signal processor (DSP).
Low current consumption of 5mA, depending on
MCU activity.
Digital phase correction and selectable gain on
both current channels for use with two current
transformers (CT) or one CT and one shunt.
Power-supply monitor (PSM) for power-on reset
and reset when the supply voltage falls below a
defined threshold.
Customer programmable 8-bit 8051 compatible
microcontroller (MCU).
Programmable MCU clock with optional low
power operating conditions.
2 x Universal Asynchronous Receiver /
Transmitters (UART) for external
communications such as programme download
and debugging.
Programmable watchdog timer (WDT) and
external system reset pin.
Real-time clock/calendar (RTC) with on-chip
digital calibration and separate battery supply
pin.
On-chip voltage reference (VREF) with small
temperature coefficient.
Low power 3.0 – 4.0MHz crystal oscillator.
SPI compatible interface for external EEPROM
memory.
Standard on-chip LCD driver (LCDD) interface.
Programmable multi-purpose I/Os (MPIO) with
selectable data direction, pull-up or pull-down
resistors and drive strength.
Mains current lead/lag status indication for
reactive energy measurement.
Low power battery operating mode for meter
reading when Mains voltage is not present.
The AS8218 and AS8228 ICs offer the following
options:
AS8218: 20 x 4 segment LCDD
9 x multi-purpose I/O (MPIO)
AS8228: 24 x 4 segment LCDD
12 x multi-purpose I/O (MPIO)
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2. General Description
The AS8218 / AS8228 are highly integrated CMOS
single-phase energy metering devices for fully
electronic LCD meter systems. The AS8218 /
AS8228 have been designed to ensure the meters
full compliance with the international Standards
IEC62052 and ANSI.
The AS8218 / AS8228 ICs include all the functions
required for conventional 1 current or 2-current
anti-tamper meters. The functions include precision
energy measurement, an 8-bit microcontroller unit
(MCU), an on-chip Liquid Crystal Display driver
(LCDD), programmable multi-purpose
Inputs/Outputs (MPIO), a real time clock/calendar
(RTC) for complex tariff functions such as time-of-
use or maximum demand billing and a Serial
Peripheral Interface (SPI) for reading data from and
writing data to an external non-volatile memory
(EEPROM).
The AS8218 / AS8228 ICs have a dedicated energy
measurement front-end, which includes an analog
front-end and programmable Digital Signal
Processor (DSP) from which active energy, mains
voltage and mains current are provided. Reactive
and apparent energy can also be calculated.
The on-chip 8-bit 8051 compatible microcontroller
is freely programmable and provides user access to
the various functional blocks. The dedicated
Universal Asynchronous Receiver / Transmitter
(UART1) in the System Control block provides
access to various system functions and blocks. A
second UART (UART2) is also provided, which may
for example be used for debugging. The on-chip
memory includes 24kByte program memory and
1kByte data memory. The meter system designer
can select the size of the external EEPROM
memory from 1kByte to 32kByte (in binary steps).
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Revision 3.0, 31-May-06
Page 1 of 123
AMSCO [ AUSTRIAMICROSYSTEMS AG ]
