UPD784938 Datasheet, PDF (406/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 16 A/D CONVERTER
(5) SAR: Successive Approximation Register
SAR is an 8-bit register in which the data for which the series resistor string voltage tap value matches the analog input
voltage value is set bit by bit starting from the most significant bit (MSB).
When data has been set up to the least significant bit (LSB) of the SAR (when A/D conversion is completed), the SAR
contents (conversion result) are stored in the A/D conversion result register (ADCR).
(6) ADCR: A/D Conversion Result Register
ADCR is an 8-bit register that holds the A/D conversion result. The conversion result is loaded into this register from
the successive approximation register (SAR) each time A/D conversion finishes.
The contents of this register approximation are undefined when RESET is input.
(7) Edge detection circuit
The edge detection circuit detects a valid edge from the interrupt request input pin (INTP5) input, and generates an
external interrupt request signal (INTP5) and A/D conversion operation external trigger.
The INTP5 pin input valid edge is specified by external interrupt mode register 1 (INTM1) (see Figure 22-2). External
trigger enabling/disabling is set by means of the A/D converter mode register (ADM) (see 16.2 A/D Converter Mode
Register (ADM)).
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Preliminary User’s Manual U13987EJ1V0UM00