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A-D CONVERTER
7902 Group User’s Manual
13-22
13.8 Single sweep mode
13.8.2 Single 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 corresponding A-D register i each time when the A-D
conversion per one pin is completed.
When step is completed, the A-D conversion interrupt request bit is set to “1.”
The A-D conversion start bit is cleared to “0,” and the A-D converter halts.
(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 conversion for all selected analog input pins are performed.
The conversion result is transferred to the A-D register i each time each when the A-D conversion
per one pin is completed.
When step is completed, the A-D conversion interrupt request bit is set to “1.”
The A-D conversion halts.
The A-D conversion start bit remains set to “1” after step . Accordingly, the operation of the A-D
converter can be performed again from step if an trigger is generated (the level at pin ADTRG
changes from “H” to “L” or from “L” to “H.”)
If an trigger is generated during the operation of the A-D converter, the operation at that point is
cancelled and is restarted from step .
Figure 13.8.2 shows the conversion operation in the single sweep mode.
Fig. 13.8.2 Conversion operation in single sweep mode
Convert input voltage at
pin AN0.
Conversion result
A-D register 0
A-D register i
A-D register 1
Conversion result
A-D converter halts.
A-D converter interrupt
request occurs.
Convert input voltage at
pin AN1.
Convert input voltage at
pin ANi.
Trigger generated