Freescale Semiconductor Demo Board DEMO9S08SH8/SG8 DEMO9S08SH8 DEMO9S08SH8 用户手册
产品代码
DEMO9S08SH8
D E M O 9 S 0 8 S H 8
A P R I L 2 7 , 2 0 0 7
U S E R G U I D E
13
USER I/O
User I/O includes 1 potentiometers, 1 Light Sensor, 2 push button switches, and 2 green LEDs
for user I/O. The User option header block enables or disables each User I/O function indi-
vidually.
for user I/O. The User option header block enables or disables each User I/O function indi-
vidually.
Potentiometer
The DEMO9S08SH8 target board provides a 5K ohm potentiometer (POT) to simulate analog
input. The POT is decoupled to minimize noise during adjustment. Potentiometer RV1 con-
nects to analog input PTA0. The figure below shows the USER enable position and associ-
ated signal for the potentiometer.
input. The POT is decoupled to minimize noise during adjustment. Potentiometer RV1 con-
nects to analog input PTA0. The figure below shows the USER enable position and associ-
ated signal for the potentiometer.
Switches
The DEMO9S08SH8 provides 2 push button switches for user input. Each push button switch
provides an active low input with a pull-up resistor bias to prevent indeterminate input condi-
tions. Pressing a push-button switch causes a low logic input on the associated input. The fig-
ure below shows the USER enable position and associated signal for each user switch.
provides an active low input with a pull-up resistor bias to prevent indeterminate input condi-
tions. Pressing a push-button switch causes a low logic input on the associated input. The fig-
ure below shows the USER enable position and associated signal for each user switch.
LED’s
The DEMO9S08SH8 target board provides 2 green LEDs for output indication. Each LED is
an active low output. Writing a low logic level to an LED output causes the associated LED to
turn on. A series, current-limit resistor prevents excessive diode current. The figure below
shows the USER enable position and associated signal for each user LED.
an active low output. Writing a low logic level to an LED output causes the associated LED to
turn on. A series, current-limit resistor prevents excessive diode current. The figure below
shows the USER enable position and associated signal for each user LED.
User Signals
The following table shows the connections for each user I/O device.
Table 6: User I/O
USER
Ref Des
Signal
Device
1
SW1
PTA2/PIA2/SDA/ADP2
Push Button Switch
2
SW2
PTA3/PIA3/SCL/ADP3
Push Button Switch
3
LED1
PTB6/SDA/XTAL
Green LED
4
LED2
PTB7/SCL/EXTAL
Green LED
5
RV1
PTA0/PIA0/ACMP1+
Potentiometer
6
RZ1
PTA1/PIA1/ACMP1-
Sensor