UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 433

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(4) When the STOP mode or IDLE mode is used, the consumption current should be reduced by clearing (0) the CS bit
(5) Once the A/D converter starts operating, conversion operations are performed repeatedly until the CS bit of the A/D
before entering the STOP or IDLE mode. If the CS bit remains set (1), the conversion operation will be stopped by
entering the STOP or IDLE mode, but the power supply to the voltage comparator will not be stopped, and therefore
the A/D converter consumption current will not be reduced.
converter mode (ADM) is cleared (0). Therefore, a superfluous interrupt may be generated if ADM setting is performed
after interrupt-related registers, etc., are set when A/D converter mode conversion, etc., is performed. The result of
this superfluous interrupt is that the conversion result storage address appears to have been shifted when the scan
mode is used. Also, when the select mode is used, the first conversion result appears to have been an abnormal value,
such as the conversion result for the other channel. It is therefore recommended that A/D converter mode conversion
be carried out using the following procedure.
<1> Write to the ADM (CS bit must be set (1))
<2> Interrupt request flag (ADIF) clearance (0)
<3> Interrupt mask flag or interrupt service mode flag setting
Operations <1> to <3> should not be divided by an interrupt or macro service. When scan mode 0 (no delay control)
is used, in particular, you should ensure that the time between <1> and <2> is less than the time taken by one A/D
conversion operation.
Alternatively, the following procedure is recommended.
<1> Stop the A/D conversion operation by clearing (0) the CS bit of the ADM.
<2> Interrupt request flag (ADIF) clearance (0).
<3> Interrupt mask flag or interrupt service mode flag setting
<4> Write to the ADM
Figure 14-13 Example of Capacitor Connection on A/D Converter Pins
Reference
Voltage Input
Analog
Input
100 to
500 pF
CHAPTER 14 A/D CONVERTER
ANI0-ANI7
AV
AV
REF1
SS
PD784026
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