AS8218 Datasheet, PDF (1/2 Pages) ams AG – Highly Integrated Single Phase 2-Current Energy Metering Integrated Circuits with Microcontroller, RTC, Programmable Multi-Purpose I/Os and LCD Driver

AS8218 / AS8228
Highly Integrated Single Phase 2-Current Energy
Metering Integrated Circuits with Microcontroller, RTC,
Programmable Multi-Purpose I/Os and LCD Driver
FEATURES
1. Key Features
- 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.
- Real-time clock/calendar (RTC) with on-chip
digital calibration and separate battery backup
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.
- Low power battery operating mode for meter
reading when Mains voltage is not present.
- The difference between the AS8218 and
AS8228 ICs are:
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)
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 that meters
can fully comply with the international Standards
IEC1036 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 and selectable 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 include 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.
Due to the large diversity of non-volatile memory
requirements for fully electronic single-phase
metering systems, the AS8218 / AS8228 ICs allow
the system designer to select the size of the
external EEPROM memory, 1kByte to 32kByte (in
binary steps).
The system timing and real time clock (RTC) has a
dedicated supply pin (VDD_BAT), which is separate
from the rest of the IC, enabling the oscillator to be
supplied with an external battery during ‘power-
Revision 2.1, 06-Oct-05
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