Features AS8218 / AS8228

Revision 2.1, 06-Oct-05

Page 2 of 2

down’. The RTC may be digitally calibrated for

oscillator frequency accuracy. The LCD Driver

(LCDD) block enables the display of information

provided by the microcontroller, directly to the LCD.

Two dedicated data register banks are provided to

simplify programming, particularly in the case

where the display data needs to be scrolled.

The programmable multi-purpose I/O pins (MPIO)

may be independently configured as dedicated

inputs or outputs. All the I/O pins are

programmable for data direction, pull-up/pull-down

resistors and drive strength (4mA/8mA). Such

functions may include LED energy consumption

pulse output, energy direction and fault condition

indication depending on current 1 or current 2

being active for the energy calculation, push button

for display scrolling, mains isolation relay control

for prepayment meters, optical interface etc.

An on-chip analog ground buffer (ABUF) and

voltage reference (VREF) ensures that no external

circuitry is required. A power-supply monitor (PSM)

provides a reset, when VDD falls below a safe

operating threshold.

The AS8218 / AS8228 ICs are available in a

LQFP64 plastic package.

3. AS8218 / AS8228 Block Diagram

System Timing &

Real Time Clock

Energy Measurement

Front End

System

Control

8051

Micro-

Controller

LCD

Driver

Multi-purpose

I/Os

SPI

Analog

Front

End

DSP

LBP3 ... 0

SC

IO11 ... 0

LSD23 ... 0

TXD

SI

SO

S_N

RXD

I2N

I2P

I1N

I1P

VN

VP

VDD_BAT

XIN

XOUT

UART1

Figure 1:

AS8218 / AS8228 block diagr am

4. Contact

austriamicrosystems AG

A 8141 Schloss Premstaetten, Austria

T. +43 3136 500 0

F. +43 3136 525 01

info@austriamicrosystems.com