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Section 12 A/D Converter
Rev. 6.00 Sep 12, 2006 page 351 of 526
REJ09B0326-0600
Bit 7
A/D Start Flag (ADSF):
Bit 7 controls and indicates the start and end of A/D conversion.
Bit 7: ADSF
Description
0
Read: Indicates the completion of A/D conversion
(initial value)
Write: Stops A/D conversion
1
Read: Indicates A/D conversion in progress
Write: Starts A/D conversion
Bits 6 to 0
Reserved Bits:
Bits 6 to 0 are reserved; they are always read as 1, and cannot be
modified.
12.3 Operation
12.3.1
A/D Conversion Operation
The A/D converter operates by successive approximations, and yields its conversion result as 8-bit
data.
A/D conversion begins when software sets the A/D start flag (bit ADSF) to 1. Bit ADSF keeps a
value of 1 during A/D conversion, and is cleared to 0 automatically when conversion is complete.
The completion of conversion also sets bit IRRAD in interrupt request register 2 (IRR2) to 1. An
A/D conversion end interrupt is requested if bit IENAD in interrupt enable register 2 (IENR2) is
set to 1.
If the conversion time or input channel needs to be changed in the A/D mode register (AMR)
during A/D conversion, bit ADSF should first be cleared to 0, stopping the conversion operation,
in order to avoid malfunction.
12.3.2
Start of A/D Conversion by External Trigger Input
The A/D converter can be made to start A/D conversion by input of an external trigger signal.
External trigger input is enabled at pin
ADTRG
when bit TRGE in AMR is set to 1. Then when
the input signal edge designated in bit INTEG5 of interrupt edge select register 2 (IEGR2) is
detected at pin
ADTRG
, bit ADSF in ADSR will be set to 1, starting A/D conversion.
Figure 12.2 shows the timing.
Summary of Contents for F-ZTAT H8/3642A Series
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Page 124: ...Section 5 Power Down Modes Rev 6 00 Sep 12 2006 page 102 of 526 REJ09B0326 0600 ...
Page 188: ...Section 6 ROM Rev 6 00 Sep 12 2006 page 166 of 526 REJ09B0326 0600 ...
Page 190: ...Section 7 RAM Rev 6 00 Sep 12 2006 page 168 of 526 REJ09B0326 0600 ...
Page 298: ...Section 9 Timers Rev 6 00 Sep 12 2006 page 276 of 526 REJ09B0326 0600 ...
Page 378: ...Section 12 A D Converter Rev 6 00 Sep 12 2006 page 356 of 526 REJ09B0326 0600 ...
Page 446: ...Section 13 Electrical Characteristics Rev 6 00 Sep 12 2006 page 424 of 526 REJ09B0326 0600 ...