A-D Converter
Mitsubishi microcomputers
M16C / 62A Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
2-126
In single sweep mode, choose functions from those listed in Table 2.7.7. Operations of the circled items
are described below. Figure 2.7.15 shows timing chart, and Figure 2.7.16 shows the set-up procedure.
2.7.7 Operation of A-D Converter (in single sweep mode)
Figure 2.7.15. Operation timing of single sweep mode
Item
Set-up
Operation clock AD
Divided-by-4 fAD / divided-
by-2 fAD / fAD
8-bit / 10-bit
External ope-amp
connection mode
Expanded analog
input pin
Not used
O
Resolution
Analog input pin
AN0 and AN1 (2 pins) / AN0
to AN3 (4 pins) / AN0 to AN5
(6 pins) / AN0 to AN7 (8 pins)
O
Software trigger
Trigger for starting A-
D conversion
O
Trigger by ADTRG
Sample & Hold
Not activated
Activated
O
Operation (1) Setting the A-D conversion start flag to “1” causes the A-D converter to start the conversion
on voltage input to the AN0 pin.
(2) After the A-D conversion of voltage input to the AN0 pin is completed, the content of the
successive comparison register (conversion result) is transmitted to A-D register 0. The A-D
converter converts all analog input pins selected by the user. The conversion result is trans-
mitted to A-D register i corresponding to each pin, every time conversion on one pin is com-
pleted.
(3) When the A-D conversion on all the analog input pins selected is completed, the A-D conver-
sion interrupt request bit goes to “1”. At this time, the A-D conversion start flag goes to “0”.
The A-D converter stops operating.
Table 2.7.7. Choosed functions
Cleared to “0” when interrupt request is accepted, or cleared by software
A-D conversion
start flag
“1”
“0”
A-D register 0
A-D register 1
φAD
A-D register i
Result
Set to “1” by software
8-bit resolution : 28
φAD cycles
10-bit resolution : 33
φAD cycles
8-bit resolution : 28
φAD cycles
10-bit resolution : 33
φAD cycles
(1) Start A-D conversion
After A-D conversion on AN0 pin is complete,
A-D converter begins converting all pins selected
A-D conversion
is complete
(2)
Note: When
φAD frequency is less than 1MHZ, sample and hold function cannot be selected.
Conversion rate per analog input pin is 49
φAD cycles for 8-bit resolution and 59 φAD cycles for 10-bit resolution.
(3)
A-D conversion
interrupt request
bit
“1”
“0”