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CHAPTER 11 A/D CONVERTER
Table 11.3-1 A/D Control Register 1 (ADC1) Bitss
Bit
Function
Bit 7
Bit 6
Bit 5
Bit 4
ANS3 to ANS0:
Analog input
channel selection
bits
These bits select which of the AN0 to AN3 pins to use as the
analog input pin. When using software activation (ADC2: EXT
= "0"), these bits can be modified to at the same time as
activating the A/D conversion or sense function (AD = "1").
Check:
Always set ANS3 to "0".
If ANS3 is "1", no pin is selected as the analog input pin.
Also, disable general-purpose port output corresponding to
the analog input pin.
Do not modify these bits when the ADMV bit is set to "1".
Note:
Pins not used as analog inputs can be used as general-
purpose ports.
Bit 3
ADI:
Interrupt request
flag bit
For the A/D conversion function:
This bit is set to "1" when the A/D conversion is completed.
For the sense function:
This bit is set to "1" when the input voltage satisfies the
condition set in the compare condition setting bit (SIFM).
An interrupt request is output for either function when both
this bit and the interrupt request enable bit (ADC2: ADIE)
are "1".
Writing "0" clears this bit. Writing "1" has no effect and
does not change the bit value.
Bit 2
ADMV:
Conversion-in-
progress flag bit
This bit indicates whether or not the A/D conversion function is
currently performing a conversion or the sense function is
currently performing a voltage comparison. The bit is set to "1"
when a conversion or comparison is in progress.
Note:
This bit is read-only. The write value has no meaning and
has no effect on the operation.
Bit 1
SIFM:
Compare
condition setting
bit
This bit has no meaning for the A/D conversion function.
For the sense function:
This bit sets the comparison condition for the input voltage
and compare voltage that generates an interrupt source.
An interrupt request is generated (ADI = "1") when the input
voltage is less than the compare voltage if the bit is "0", and
when the input voltage is greater than the compare voltage
if the bit is "1".
No interrupt request is generated if the input voltage and
compare voltage are equal.
When using software activation (ADC2: EXT = "0"), this bit
can be modified to at the same time as starting the sense
function (AD = "1").
Check:
Do not modify these bits when the ADMV bit is set to "1".