Overview Of A/D Converter - Fujitsu F2MC-8L MB89620 Series Hardware Manual

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13.

Overview of A/D Converter

The A/D converter can be selected to function either as an 8-bit successive
approximation type A/D conversion or as a sense function. The sense function
performs a high-speed comparison between the input voltage and a set voltage. Both
functions select one input signal from the eight analog input pin channels and can be
activated either by software, by an internal clock, or by an external clock.
The sense function can be used in applications such as checking battery capacitance
or temperature fluctuation.
n A/D Conversion Function
The A/D conversion function converts the analog voltage (input voltage) input to an analog input
pin to an 8-bit digital value.
• Selects one input from eight analog input pins.
Conversion speed is 44 instruction cycles (17.6 µ s for a 10 MHz source oscillation).
•
• Generates an interrupt when A/D conversion completes.
• Conversion completion can also be determined by software.
The following methods are available to activate A/D conversion:
• Activation by software
• Continuous activation by a timebase timer output (divide-by-2
• Continuous activation synchronized with an external clock input
Check: Continuous activation by an externally input clock is not available on the MB89628R, MB89629R,
Reference: See Chapter 14, "Clock Monitor Function" for details of the clock monitor function.
n Sense Function
The sense function compares the analog voltage (input voltage) input to an analog input pin
with the voltage (compare voltage) corresponding to the value set in the A/D data register
(ADCD), and determines which voltage is higher or lower.
• Selects one input from eight analog input pins.
Compare speed is 12 instruction cycles (4.8 µ s for a 10 MHz source oscillation).
•
• Generates an interrupt when the comparison condition is satisfied.
The following methods are available to activate the sense function:
• Activation by software
• Continuous activation by a timebase timer output (divide-by-2
• Continuous activation synchronized with an external clock input
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CHAPTER 13 A/D CONVERTER
and MB89P629 if the clock monitor function is used.
8
source oscillation)
8
source oscillation)
MB89620 series