A-D CONVERTER
7902 Group User’s Manual
13-24
13.9 Repeat sweep mode
13.9.2 Repeat sweep mode operation
(1) When an internal trigger is selected
The A-D converter starts its operation for the input voltage at pin AN0 when the A-D conversion start
bit is set to “1.”
The A-D conversion for the input voltage at pin AN0 is completed after 49 cycles of
φAD in the 8-
bit resolution mode, or 59 cycles of
φAD in the 10-bit resolution mode. Then, the contents of the
successive approximation register (conversion result) are transferred to the A-D register 0.
The A-D conversions for all selected analog input pins are performed.
The conversion result is transferred to the correponding A-D register i each time when the A-D
conversion per one pin is completed.
The A-D conversions for all selected analog input pins are performed again.
The A-D converter repeates its operation until the A-D conversion start bit is cleared to “0” by
software.
(2) When an external trigger is selected
The A-D converter starts its operation for the input voltage at pin AN0 when the input level at pin ADTRG
changes from “H” to “L” (when the external trigger polarity select bit = “0”) or from “L” to “H” (when the
external trigger polarity select bit = “1”) while the A-D conversion start bit = “1.”
The A-D conversion for the input voltage at pin AN0 is completed after 49 cycles of
φAD in the 8-
bit resolution mode, or 59 cycles of
φAD in the 10-bit resolution mode. Then, the contents of the
successive approximation register (conversion result) are transferred to the A-D register 0.
The A-D conversions for all selected analog input pins is performed.
The conversion result is transferred to the correponding A-D register i each time when the A-D
conversion per one pin is completed.
The A-D conversion for all selected analog input pins are performed again.
The A-D converter repeates its operation until the A-D conversion start bit is cleared to “0” by
software.
When the level at pin ADTRG changes from “H” to “L” or from “L” to “H” during the operation of the
A-D converter, the operation at that point is cancelled and is restarted from step .
Figure 13.9.2 shows the conversion operation in the repeat sweep mode.
Fig. 13.9.2 Conversion operation in repeat sweep mode
Convert input voltage at pin AN0.
Conversion result
A-D register 0
A-D register i
A-D register 1
Conversion result
Convert input voltage at pin AN1.
Convert input voltage at pin ANi.
Trigger generated