15. A/D Converter
puorG92/C61M
page 241
854fo7002,03.raM21.1.veR
2110-1010B90JER
NOTES:
1. Set the larger value than the value of the timer B0 register to the timer B1 register. The count source for timer B0
and timer B1 must be the same.
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.
3. AN0
0 to AN07, AN 20 to AN27, and
AN3
0
to AN3
2
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 voltages 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 with the AN1 pin. Table 15.10 shows the
delayed trigger mode 0 specifications. Figure 15.19 shows the operation example in delayed trigger
mode 0. Figures 15.20 and 15.21 show each flag operation in the ADSTAT0 register that corresponds to
the operation example. Figure 15.22 shows registers ADCON0 to ADCON2 in delayed trigger mode 0.
Figure 15.23 shows the ADTRGCON register in delayed trigger mode 0 and Table 15.11 shows the
trigger select bit setting in delayed trigger mode 0.
Item Specification
Function Bits SCAN1 and SCAN0 in the ADCON1 register and bits ADGSEL1 and ADGSEL0
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
underflow generation starts AN
0 pin conversion. Timer B1 underflow generation
starts conversion after the AN1 pin.
(1)
A/D Conversion Start AN0 pin conversion start condition
•When 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
AN
1 pin conversion start condition
•When Timer B1 underflow is generated during A/D conversion of the AN
0 pin, the
input voltage of the AN
1 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)
(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)
(3)
Readout of A/D conversion Readout one of registers AN0 to AN7 that corresponds to the selected pins
result
Table 15.10 Delayed Trigger Mode 0 Specifications
To Next Page
Loading...
Need help?
General
