Calculating The A-D Conversion Time - Renesas M32R/ECU Series User Manual

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11.3.4 Calculating the A-D Conversion Time

The A-D conversion time is expressed by the sum of dummy cycle time and actual execution cycle time. The
following shows each time factor necessary to calculate the conversion time.
1. Start dummy time
A time from when the CPU executed the A-D conversion start instruction to when the A-D Converter
starts A-D conversion
2. A-D conversion execution cycle time
If sample-and-hold is enabled, the sampling time is included in this execution cycle time.
3. Comparate execution cycle time
4. End dummy time
A time from when the A-D Converter has finished A-D conversion to when the CPU can stably read out
the conversion result from the A-D data register.
5. Scan to scan dummy time
A time during single-shot or continuous scan mode from when the A-D Converter has finished A-D
conversion on a channel to when it starts A-D conversion on the next channel.
The equation to calculate the A-D conversion time is as follows:
A-D conversion time = Start dummy time + Execution cycle time
Note: • Enclosed in ( ) are the conversion time required for the second and subsequent channels
(1) Calculating the conversion time during A-D conversion mode
The following schematically shows the method for calculating the conversion time during A-D conversion mode.
<Single mode>
A-D conversion
start trigger
Start dummy
<Scan mode>
Start dummy
Figure 11.3.3 Conceptual Diagram of A-D Conversion Time
(+ Scan to scan dummy time + Execution cycle time
+ Scan to scan dummy time + Execution cycle time
+ Scan to scan dummy time .... + Execution cycle time)
+ End dummy time
to be converted in scan mode.
Convert operation
starts
Execution cycle
(Channel 0)
Execution cycle
scan dummy
11.3 Functional Description of A-D Converters
Transferred to the
A-D data register Completed
End dummy
Scan to
scan dummy
(Last channel)
Scan to
Execution cycle
11-36
A-D Converters
(Channel 1)
Execution cycle
End dummy
32180 Group User's Manual (Rev.1.0)