SAF-C164SM Infineon Technologies, SAF-C164SM Datasheet - Page 330

• Manufacturer Part Number: SAF-C164SM
• Description: 16-Bit CMOS Microcontroller
• Manufacturer: Infineon Technologies

Wait for ADDAT Read Mode
In ADC default mode, if a previous conversion result has not been read out of register
ADDAT by the time a new conversion is complete, the previous result in register ADDAT
is lost because it is overwritten by the new value, and the A/D overrun error interrupt
request flag ADEIR will be set.
To avoid error interrupts and the loss of conversion results (especially when using
continuous conversion modes), the ADC can be switched to “Wait for ADDAT Read
Mode” by setting bit ADWR in register ADCON.
If the value in ADDAT has not been read by the time the current conversion is complete,
the new result is stored in a temporary buffer and the next conversion is suspended
(ADST and ADBSY will remain set in the meantime, but no end-of-conversion interrupt
will be generated). After reading the previous value from ADDAT, the temporary buffer
is copied into ADDAT (generating an ADCIR interrupt) and the suspended conversion is
restarted. This mechanism applies to both single and continuous conversion modes.
Note: In standard mode, continuous conversions are executed at a fixed rate
Figure 18-4 Wait for Read Mode Example
User’s Manual
Generate Interrupt
Result of Channel:
Read of ADDAT;
Temp-Latch Full
(determined by the conversion time). In “Wait for ADDAT Read Mode” there may
be delays due to suspended conversions. However, this affects the conversions
only if the CPU (or PEC) cannot keep up with the conversion rate.
Write ADDAT
of Channel..
ADDAT Full
Conversion
Request
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18-8
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Hold Result in
Temp-Latch
1
wait
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Analog/Digital Converter
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C164CM/C164SM
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Derivatives
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V1.0, 2002-02
MCA01970
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