UPD784938 Datasheet, PDF (403/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 16 A/D CONVERTER
The µPD784938 incorporates an analog/digital (A/D) converter with 8 multiplexed analog inputs (ANI0 to ANI7).
The successive approximation conversion method is used, and the conversion result is held in the 8-bit A/D conversion
result register (ADCR). This allows fast, high-precision conversion to be performed.
There are two modes for starting A/D conversion, as follows:
• Hardware start: Conversion started by trigger input (INTP5).
• Software start: Conversion started in accordance with A/D converter mode register (ADM) bit setting.
After start-up, there are two operation modes, as follows:
• Scan mode: Multiple analog inputs are selected in order, and conversion data is obtained from all pins.
• Select mode: One pin is used as the analog input, and conversion values are obtained in succession.
Stoppage of all the above modes and conversion operations is specified by the ADM register.
When the conversion result is transferred to the ADCR, an INTAD interrupt request is generated. This allows conversion
values to be transferred to memory in succession by means of macro service.
Cautions 1. Apply a voltage same as the supply voltage (AVDD) to the reference voltage input pin (AVREF1) of
this product.
2. When port 7 is used for both output port and A/D input, do not write to output port during A/D
conversion operations.
16.1 Configuration
The A/D converter configuration is shown in Figure 16-1.
Preliminary User’s Manual U13987EJ1V0UM00
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