Operations Of 8/10-Bit A/D Converter - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 19 8/10-BIT A/D CONVERTER

19.3 Operations of 8/10-bit A/D Converter

The 8/10-bit A/D converter operates based on a sequential comparison method and
has a 10-bit resolution.
The 8/10-bit A/D converter has only one combined 10-bit register for storing results of
conversion. Data in the individual data conversion registers (ADCR2 and ADCR1) is
updated whenever one conversion operation ends. The converter therefore does not
support continuous conversion processing. It is recommended that conversion be
performed while transferring conversion data to memory using the µ µ µ µ DMA function of
2
F MC-16LX.
This section describes the operations of the 8/10-bit A/D converter.
I Operation modes
The operation modes used by the converter are described below.
❍ Single Mode
In this mode, analog input set by the bits ANS and ANE is sequentially converted. The converter
stops conversion operation when conversion up to the end channel set by the bit ANE is
finished. If the start and end channels are the same, one-channel conversion will be performed.
(ANS = ANE)
Example:
ANS = 000, ANE = 011
Start --> AN0 --> AN1 --> AN2 --> AN3 --> End
ANS = 010, ANE = 010
Start --> AN2 --> End
❍ Continuous Mode
In this mode, analog input set by the bits ANS and ANE is sequentially converted. The converter
continues conversion operation by returning to ANS analog input when conversion up to the end
channel set by the bit ANE is finished. One-channel conversion operation will continue if the
start and end channels are the same. (ANS = AME)
Example:
ANS = 000, ANE = 011
Start --> AN0 --> AN1 --> AN2 --> AN3 --> AN0 ...... --> Repeat
ANS = 010, ANE = 010
Start --> AN2 --> AN2 --> AN2 ...... --> Repeat
When conversion is performed in continuous mode, conversion will be repeated until the BUSY
bit is set by writing "0".
Set the BUSY bit to "0" to forcibly stop operation.
When operation is stopped forcibly, data before the completion of conversion will be stored in
the conversion registers.
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