Datasheet

Chapter 9 Analog-to-Digital Converter (S08ADC10V1)
MC9S08SG32 Data Sheet, Rev. 8
146 Freescale Semiconductor
Figure 9-13. Initialization Flowchart for Example
9.6 Application Information
This section contains information for using the ADC module in applications. The ADC has been designed
for integration into a microcontroller used 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
DDA
and V
SSA
) available as separate pins on
some devices. V
SSA
is shared on the same pin as the MCU digital V
SS
on some devices. On other devices,
V
SSA
and V
DDA
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
DDA
and V
SSA
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