M16C65 Datasheet, PDF (718/829 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/60

Under development
M16C/65 Group
Preliminary Specification
This is a preliminary specification and is subject to change.
27. A/D Converter
27.7.6 A/D Operation Mode Change
When A/D operation mode has been changed, re-select analog input pins by using bits CH2 to CH0 in
the ADCON0 register or bits SCAN1 to SCAN0 in the ADCON1 register.
27.7.7 State When Forcibly Terminated
If A/D conversion in progress is halted by setting the ADST bit in the ADCON0 register to 0, the
conversion result is undefined. In addition to that, the unconverted ADi register may also become
undefined. Do not use any ADi registers when setting the ADST bit to 0 by a program during A/D
conversion.
27.7.8 A/D Open-Circuit Detection Assist Function
The conversion result in open-circuit depends on the external circuit. Use this function only after careful
evaluation for the system. Do not use this function when VCC1 > VCC2.
When A/D conversion starts after changing the AINRST register, follow these procedures:
(1) Change bits AINRST1 to AINRST0 in the AINRST register.
(2) Wait for one cycle of φAD.
(3) Set the ADST bit in the ADCON0 register to 1 (A/D conversion start).
27.7.9 Detection of Completion of A/D Conversion
In one-shot mode and single sweep mode, use the IR bit in the ADIC register to detect completion of
A/D conversion. When not using interrupt, set the IR bit to 0 by a program after the detection.
When 1 is written to the ADST bit in the ADCON0 register, the ADST bit becomes 1 (A/D conversion
start) after start processing time (refer to Table 27.7 “Cycles of A/D Conversion Item”) elapses. When
reading the ADST bit shortly after writing 1, 0 (A/D conversion stop) may be read.
Write 1 to the ADST bit by a
program.
ADST bit in the
ADCON0 register
IR bit in the ADIC
register
Start
processing time
Figure 27.16 ADST Bit Operation
A/D conversion
Set to 0 by acceptance of an interrupt
request or by a program.
27.7.10 Register Settings
Set the CKS3 bit, and then set other A/D converter related registers. Also, after changing the CKS3 bit,
set the A/D converter related registers again. Note that bits in the ADCON2 register and the CKS3 bit
can be set simultaneously.
REJ09B0484-0030 Rev.0.30 Sep 09, 2008
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