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M16C/28 Group
Under development Preliminary specification
Specifications in this manual are tentative and subject to change.
15. A-D Converter
Rev.0.60 2004.02.01
page 223 of N
REJ09B0047-0060Z
Note 1. Set the larger value than the value of the timer B0 register to the timer B1 register.
Note 2. Do not write “1” (A-D conversion started) to the ADST bit in delayed trigger mode 0. When write “1”,
unexpected interrupts may be generated.
Note 3. AN00 to AN07 and AN20 to AN27 can be used in the same way as AN0 to AN7. However, all input pins need to
belong to the same group.
15.1.7 Delayed Trigger Mode 0
In delayed trigger mode 0, analog voltage applied to the selected pins are converted one-by-one to a
digital code. The delayed trigger mode 0 used in combination with A-D trigger mode of Timer B. The
Timer B0 underflow starts a single sweep conversion. After completing the AN0 pin conversion, the AN1
pin is not sampled and converted until the Timer B1 underflow is generated. When the Timer B1 under-
flow is generated, the single sweep conversion is restarted after the AN1 pin. Table 15.1.7.1 shows the
delayed trigger mode 0 specifications. Figure 15.1.7.1 shows the operation example in delayed trigger
mode 0. Figure 15.1.7.2 to Figure 15.1.7.3 show each flag operation in the ADSTAT0 register that corre-
sponds to the operation example. Figure 15.1.7.4 shows the ADCON0 to ADCON2 registers in delayed
trigger mode 0. Figure 15.1.7.5 shows the ADTRGCON register in delayed trigger mode 0 and Table
15.1.7.2 shows the trigger select bit setting in delayed trigger mode 0.
Item
Specification
Function
The SCAN1 to SCAN0 bits in the ADCON1 register and ADGSEL1 to ADGSEL0 bits in
the ADCON2 register select pins. Analog voltage applied to the input voltage of the
selected pins are converted one-by-one to the digital code. At this time, Timer B0 under
flow generation starts AN0 pin conversion. Timer B1 underflow generation starts con-
version after the AN1 pin. (Note 1)
A-D Conversion Start
AN0 pin conversion start condition
After Timer B0 underflow is generated if Timer B0 underflow is generated again
before Timer B1 underflow is generated , the conversion is not affected
When Timer B0 underflow is generated during A-D conversion of pins after the AN1
pin, conversion is halted and the sweep is restarted from the AN0 pin
again
AN1 pin conversion start condition
When Timer B1 underflow is generated during A-D conversion of the AN0 pin, the
input voltage of the AN1 pin is sampled. The AN1 conversion and the rest of the
sweep start when AN0 conversion is completed.
A-D Conversion Stop
When single sweep conversion from the AN0 pin is completed
Condition
Set the ADST bit to "0" (A-D conversion halted)(Note 2)
Interrupt Request
A-D conversion completed
Generation Timing
Analog Input Pin
Select from AN0 to AN1 (2 pins), AN0 to AN3 (4 pins), AN0 to AN5 (6 pins) and
AN0 to AN7 (8 pins)(Note 3)
Readout of A-D Conversion Result Readout one of the AN0 to AN7 registers that corresponds to the selected pins
Table 15.1.7.1 Delayed Trigger Mode 0 Specifications