SAB80515 Datasheet, PDF (74/270 Pages) Siemens Semiconductor Group – 8-Bit Single-Chip Microcontroller Family

On-Chip Peripheral Components
7.4.1 Function and Control
7.4.1.1 lnitialization and Input Channel Selection
Special function register ADCON which is illustrated in figure 7-26 is used to set the operating
modes, to check the status, and to select one of eight analog input channels.
Figure 7-26
Special Function Register ADCON (Address 0D8H)
0DFH 0DEH 0DDH 0DCH 0DBH 0DAH 0D9H 0D8H
0D8H BD CLK
–
BSY ADM MX2 MX1 MX0 ADCON
These bits are not used in controlling A/D converter functions.
Bit
MX0
MX1
MX2
ADM
BSY
Function
Select 8 input channels of the A/D converter, see table 7-6
A/D conversion mode. When set, a continuous conversion is selected. If
ADM = 0, the converter stops after one conversion.
Busy flag. This flag indicates whether a conversion is in progress
(BSY = 1). The flag is cleared by hardware when the conversion is
completed.
Register ADCON contains two mode bits. Bit ADM is used to choose the single or continuous
conversion mode. In single conversion mode only one conversion is performed after starting, while
in continuous conversion mode after the first start a new conversion is automatically started on
completion of the previous one.
The busy flag BSY (ADCON.4) is automatically set when a conversion is in progress. After
completion of the conversion it is reset by hardware. This flag can be read only, a write has no
effect. There is also an interrupt request flag IADC (IRCON.0) that is set when a conversion is
completed. See section 8 for more details about the interrupt structure.
Semiconductor Group
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