MITSUBISHI MICROCOMPUTERS
M37754M8C-XXXGP, M37754M8C-XXXHP
M37754S4CGP, M37754S4CHP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(2) Repeat mode
(5) Repeat sweep mode 1
Repeat mode is selected when bit 3 of A-D control register 0 is “1”,
Repeat sweep mode 1 is selected when bit 3 of A-D control register
0 is “1”, bit 4 is “1” and bit 2 of A-D control register 1 is “1”.
The difference from the repeat sweep mode 0 is that A-D conversion
for one unselected pin is performed each time when A-D conversion
for selected pins is completed and A-D conversion is repeated once
again from AN0 pin. The number of analog input pins to be swept is
also different.
bit 4 is “0” and bit 2 of A-D control register 1 is “0”.
The operation of this mode is the same as the operation of one-shot
mode except that when A-D conversion of the selected pin is com-
plete and the result is stored in theA-D register, conversion does not
stop, but is repeated.
No interrupt request is generated in this mode. Furthermore, if soft-
ware trigger is selected, the A-D conversion start bit is not cleared.
The contents of the A-D register can be read at any time.
Be sure not to write to the A-D register corresponding to the pins se-
lected for a comparator during operation.
The analog input pins for repeatedly sweep are selected with bits 1
and 0 of A-D control register 1. The contents of these pins are used
to select one pin, two pins, three pins, or four pins.
The unselected pins are converted from the pin next to the pins se-
lected as repeat sweep pins. No interrupt request is generated. Fur-
thermore, if software trigger is selected, the A-D conversion start bit
is not cleared.
(3) Single sweep mode
Single sweep mode is selected when bit 3 of A-D control register 0
is “0”, bit 4 is “1” and bit 2 of A-D control register 1 is “0”.
In the single sweep mode, the number of analog input pins to be
swept can be selected. Analog input pins are selected by bits 1 and
0 of the A-D control register 1 (address 1F16). Two pins, four pins,
six pins, or eight pins can be selected as analog input pins, depend-
ing on the contents of these bits.
The A-D register can be read at any time.
Be sure not to write to the A-D register corresponding to the pins se-
lected for a comparator during operation.
Note: Clear the interrupt request bit of the A-D interrupt control reg-
ister (bit 3 at address 7016) before using the A-D interrupt. It is
because the interrupt request bit is undefined just after reset.
A-D conversion is performed only for selected input pins. After A-D
conversion is performed for input of AN0 pin, the conversion result
is stored in A-D register 0, and in the same way, A-D conversion is
performed for selected pins one after another. After A-D conversion
is performed for all selected pins, the sweep is stopped.
A-D conversion can be started with a software trigger or with an ex-
ternal trigger input. A software trigger is selected when bit 5 is “0”
and an external trigger is selected when it is “1”.
When a software trigger is selected, A-D conversion is started when
A-D control register 0 bit 6 (A-D conversion start bit) is set to “1.”
When A-D conversion of all selected pins end, the interrupt request
bit of the A-D conversion interrupt control register is set to “1.” At the
same time, A-D conversion start bit is cleared to “0” and A-D conver-
sion stops.
When an external trigger is selected, A-D conversion starts when
_____
the A-D conversion start bit is “1” and the ADTRG input changes from
“H” to “L”. In this case, the A-D conversion result which is stored in
_____
the A-D register 7 becomes invalid because the ADTRG pin is multi-
plexed with AN7 pin.
The operation by external trigger is the same as that by software
trigger except that the A-D conversion start bit is not cleared to “0”
after A-D conversion and a retrigger can be available during A-D
conversion.
(4) Repeat sweep mode 0
Repeat sweep mode 0 is selected when bit 3 of A-D control register
0 is “1”, bit 4 is “1” and bit 2 of A-D control register 1 is “0”.
The difference from the single sweep mode is that A-D conversion
does not stop after conversion for all selected pins, but repeats
again from the AN0 pin. The repeat is performed among the selected
pins. Also, no interrupt request is generated. Furthermore, if soft-
ware trigger is selected, the A-D convension start bit is not cleared.
The A-D register can be read at any time.
Be sure not to write to the A-D register corresponding to the pins se-
lected for a comparator during operation.
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RENESAS [ RENESAS TECHNOLOGY CORP ]
