Atmel AT89STK-09, User Manual

AT89STK-09 User Guide

2-4

 7521B–SCR–10/05

Section 2

Hardware

The AT89STK09 requires power supply, clock signal , smart card and TWI commands
to run. U1 connector is used to connect the AT83C26 host pins to the host microcontrol-
ler. The U1 connector pins are described on Table 2-1.

All passive components needed (inductors, capacitors) are soldered on board.

2.1

Power Supply

The host microcontroller signals voltage and the AT83C26 power supply are VCC. The
voltage range (VCC) is 3V to 5.5V, the maximum current consumption IVcc is about
250mA when all DC/DC convertors and LDO are activated. (Conditions : Vcc = 3V
60mA DC/DCa, 70mA DC/DCb).

2.2

Jumper 
Configuration

The AT83C26 board has one jumper in order to set complete SC2 configuration.

The complete SC2 configuration (Smart Card including CC4 & CC8) is done by SW1
solder pad.

2.3

Host 
Microcontroller 
Connection

The host microcontroller must provide the signals:

•

VCC, VSS : Power supply signals - 3 - 5.5V @ 250mA

•

EVCC can be used when the Vcc host and Vcc are different. Generally the EVCC is 
connected to VCC.

•

BYPASS is used to activate the low power consumption when connected to the host 
microcontroller (high level must be supplied) - Generally the BYPASS is connected 
to the ground.

•

A2, A1 : TWI address - Generally A2 = 0 and A1 = 0 during Reset

•

SDA, SCL : TWI signals to transmit/receive commands/status

Caution : TWI pull-ups have to be on the host microcontroller board

•

CLK signal is connected to host clock signal 

Caution : The logic inverter (HC04 or other) is recommended if source clock is supplied
by output crystal oscillator buffer.

•

INT (Interrupt) : This signal must be connected to host interrupt input

•

CRST signal is connected to RST host microcontroller signal 

•

CCLK signal is connected to the host smart card interface signal