AN1740 Freescale Semiconductor / Motorola, AN1740 Datasheet - Page 20

• Manufacturer Part Number: AN1740
• Description: Applications Using the Analog Subsystem on MC68HC05JJ/JP Series Microcontrollers
• Manufacturer: Freescale Semiconductor / Motorola

Application Note
20
NOTE:
user’s software code, but they can be a problem if they are overlooked
in the application.
The most common cause of unwanted input current or low input
impedance is a failure to turn off the input pulldown devices on port B.
This is accomplished by writing logical 1s to the desired PDIB bits in the
PDRB at location $0011.
Freescale Semiconductor, Inc.
10000
1000
100
10
For More Information On This Product,
1
1
Figure 9. Typical Channel AC Input Impedance
Go to: www.freescale.com
10
100
FREQUENCY – HZ
DIVIDED
1 K
DIRECT
10 K
100 K
MOTOROLA
AN1740
1 M