UPD784915B Datasheet, PDF (40/86 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784915B, 784916B
3.8 A/D Converter
The µPD784916B has an analog-to-digital (A/D) converter with 12 multiplexed analog inputs (ANI0 to ANI11).
This A/D converter is of successive approximation type, and the conversion result is held by an 8-bit A/D conversion
result register (ADCR) (conversion time: 10 µs at fCLK = 8 MHz).
A/D conversion can be started in the following two modes:
• Hardware start : Conversion is started by a hardware trigger^Note.
• Software start : Conversion is started by setting the A/D conversion mode register (ADM).
After conversion has been started, the A/D converter operates in the following modes:
• Scan mode : Sequentially selects more than one analog input to obtain data to be converted from all the pins.
• Select mode: Use only one pin for analog input to obtain successive data.
When the conversion result is transferred to ADCR, interrupt request INTAD is generated. By processing this
interrupt with the macro service, the conversion result can be successively transferred to memory.
A mode in which starting A/D conversion of the next pin is kept pending until the value of ADCR is read is also
available. When this mode is used, reading the conversion result by mistake when timing is shifted because an
interrupt is disabled can be prevented.
Note A hardware trigger can be one of the following coincidence signals, one of which is selected by the trigger
source select register 1 (TRGS1):
• TM0-CR01 coincidence signal
• TM0-CR02 coincidence signal
• TM1-CR13 coincidence signal
• TM5-CR50 coincidence signal
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