FUJITSU MB91F109 FR30 - Manual (Page 304)

280
CHAPTER 11 A/D CONVERTER (Successive approximation type)
11.6 Notes on Using the A/D Converter
This section provides notes on using the A/D converter
■ Notes on Using the A/D Converter
❍ Using an external trigger or internal timer to start the A/D converter
The A/D start cause bits STS1 and STS0 of the ADCS register specify whether an external
trigger or the internal timer is used to start the A/D converter. In this case, set the external
trigger or internal timer input value at the inactive side. Setting it on the active side causes
malfunction.
When setting STS1 and STS0, set the ATGX and reload timer as follows: ATGX = "1" input and
reload timer (channel 2) = "0" output.
■ Other Notes on Using the A/D Converter
If the external impedance is higher than the specified value, analog input values cannot be
sampled within the specified sampling time and accordingly normal conversion results cannot
be obtained.