Datasheet

Chapter 9 Analog-to-Digital Converter (S08ADC10V1)
MC9S08SH8 MCU Series Data Sheet, Rev. 3
Freescale Semiconductor 143
Figure 9-14. Initialization Flowchart for Example
9.6 Application Information
This section contains information for using the ADC module in applications. The ADC has been designed
to be integrated into a microcontroller for use in embedded control applications requiring an A/D
converter.
9.6.1 External Pins and Routing
The following sections discuss the external pins associated with the ADC module and how they should be
used for best results.
9.6.1.1 Analog Supply Pins
The ADC module has analog power and ground supplies (V
DDAD
and V
SSAD
) which are available as
separate pins on some devices. On other devices, V
SSAD
is shared on the same pin as the MCU digital V
SS
,
and on others, both V
SSAD
and V
DDAD
are shared with the MCU digital supply pins. In these cases, there
are separate pads for the analog supplies which are bonded to the same pin as the corresponding digital
supply so that some degree of isolation between the supplies is maintained.
When available on a separate pin, both V
DDAD
and V
SSAD
must be connected to the same voltage potential
as their corresponding MCU digital supply (V
DD
and V
SS
) and must be routed carefully for maximum
noise immunity and bypass capacitors placed as near as possible to the package.
YES
NO
RESET
INITIALIZE ADC
ADCCFG = $98
ADCSC1 = $41
ADCSC2 = $00
CHECK
COCO=1?
READ ADCRH
THEN ADCRL TO
CLEAR COCO BIT
CONTINUE