
7751 Group User’s Manual
8–25
A-D CONVE R T E R
8.8.2 Single sweep mode operation description
(1) When an internal trigger is selected
The A-D converter starts conversion for the input voltage from the AN
0
pin starts when the A-D
conversion start bit is set to “1.”
The A-D conversion of the input voltage from the AN
0
pin is completed after 49 cycles of
φ
AD
in
the 8-bit mode, or 59 cycles of
φ
AD
in the 10-bit mode. Then, the contents of the successive
approximation register (conversion result) are transferred to the A-D register 0.
The operation to all selected analog input pins is performed.
The conversion result is transferred to the A-D register i each time each pin is converted.
When the 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 stops operation.
(2) When an external trigger is selected
The A-D converter starts conversion for the input voltage from the AN
0
pin when the input level to
the
AD
TRG
pin changes from “H” to “L” while the A-D conversion start bit is “1.”
The A-D conversion of the input voltage from the AN
0
pin is completed after 49 cycles of
φ
AD
in
the 8-bit mode, or 59 cycles of
φ
AD
in the 10-bit mode. Then, the contents of the successive
approximation register (conversion result) are transferred to the A-D register 0.
The operation to all selected analog input pins is performed.
The conversion result is transferred to the A-D register i each time each pin is converted.
When the step
is completed, the A-D conversion interrupt request bit is set to “1.”
The A-D conversion stops operation.
The A-D conversion start bit remains set to “1” after the operation is completed. Accordingly, the
operation of the A-D converter can be performed again from step
when the level of the
AD
TRG
pin changes from “H” to “L.”
When the level of the
AD
TRG
pin changes from “H” to “L” during operation, the operation at that point
is cancelled and is restarted from step
.
Figure 8.8.2 shows the conversion operation in the single sweep mode.
8.8 Single sweep mode