Operations Of 8/10-Bit A/D Converter - Fujitsu MB90480 Series Hardware Manual

CHAPTER 17 8/10-BIT A/D CONVERTER

17.5 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 register for storing results of conversion (10-
bit). Data register (ADCR1 and ADCR2) 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 μDMAC function of F
This section describes the operations of the 8/10-bit A/D converter.
■
Operation modes
❍ 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 (ANS = ANE), one-channel conversion will
be performed.
Example:
ANS = 000
Start → AN0 → AN1 → AN2 → AN3 → End
ANS = 010
Start → AN2 → End
Note:
The A/D conversion ends without restarting when the restart and the end of the A/D conversion
occur at the same time, and "300
so that neither the A/D conversion comeback movement nor the end may occur at the same time.
❍ 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
Start → AN0 → AN1 → AN2 → AN3 → AN0 ...... Repeat
ANS = 010
Start → AN2 → AN2 → AN2 ...... Repeat
When conversion is performed in continuous mode, conversion operation will be repeated until
the BUSY bit is set by writing "0".
368
2
MC-16LX.
, ANE = 011
B B
, ANE = 010
B B
" is stored in data register (ADCR1/0). Therefore, please restart
H
, ANE = 011
B B
, ANE = 010
B B