Precautions On The Using A/D Converter - Fujitsu FR60 Hardware Manual

CHAPTER 12 A/D CONVERTER

12.4 Precautions on the Using A/D Converter

This section contains precautions on using the A/D converter.
■ Precautions on Using the A/D Converter
To start the A/D converter using an external trigger or an internal timer, set the A/D start source
bits (STS1 and STS0) of the ADCS register. At this time, the input value of an external trigger
or an internal timer must be set to inactive. If it is set to active, a malfunction occurs.
If STS1 and STS0 are set, set ATG=1 input and reload timer (channel 1)=0 output.
A correct conversion result will not be obtained if the external impedance exceeds the specified
value, since then the analog input value cannot be sampled within the specified sampling time.
❍ Restart of the A/D conversion
When the A/D conversion mode selection bits (MD1 and MD0) are set to "00
A/D conversion is enabled. In this mode, software start (STS1 and STS0 = 00
set. Restart in the following procedures.
(1) Clear the INTE bit to "0".
(2) Write the STRT bit to "1" and the INTE bit to "0" at the same time.
When the A/D conversion mode selection bits (MD1 and MD0) are set to "01
A/D conversion is disabled. When restarting and ending of A/D conversion occurred
simultaneously, restart operation is not executed, A/D conversion is terminated, and "300
is stored in the data register (ADCR1/ADCR0). Therefore, perform restart operation not to
generate restarting and ending of A/D conversion simultaneously.
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