Atmel STK502 - Manual (Page 18)

Using the STK502 Top Module
2-12 STK502 User Guide
2528A–AVR–11/02
2.7.1.1 AREF Switch The switch named AREF selects the input to the AREF-pin on the ATmega169.
Figure 2-18. AREF Switch
Positions:
AREF: In this position the AREF from the STK500 is connected to the AREF pin on
the ATmega169. This is the default position.
VREF: In this position the VREF from the 1.263V voltage reference on the STK502 is
connected to the AREF pin on the ATmega169. Select this position in order to run the
code in Application Note “AVR064: STK502 – A Temperature Monitoring System with
LCD Output”
2.7.1.2 PF[1:0] Switch The PF[1:0] switch selects the input to the PF1 and PF0 pins (ADC channel 1/0) on the
ATmega169.
Figure 2-19. PF[1:0] Switch
Positions:
PIN: In this position the PF0 and PF1 are from the PORTF on the STK502 are
connected to the PF0 and PF1 on the ATmega169. Default position.
Sensor: In this position the pin 1 from the screw-terminal on the STK502 are
connected to PF0 on the ATmega169, and the pin 2 from the screw-terminal are
connected to PF1 on the ATmega169. Select this position in order to run the code in
Application Note “AVR064: STK502 – A Temperature Monitoring System with LCD
output”
In the sensor position both PF0 and PF1 are connected to the senor pins, regardless of
using single ended or differential ADC-measurements in the application. This means
that it's not possible to use PF1 as an ordinary I/O-port even though only PF0 (single
ended) is used with the ADC.
AREF
AVR
From
STK500
STK502
STK502
AREF
Switch
Voltage refernce
for the sensor
VREF
AREF
PF0 (ADC0)
AVR
PF1 (ADC1)
PORTF0
Sensor
pin 1
PORTF1
Sensor
pin 2
PF[1:0]
Switch