Notes On Using Prescaler - Fujitsu 8FX Hardware Manual

MB95630H Series
3.10

Notes on Using Prescaler

This section provides notes on using the prescaler.
The prescaler operates with the machine clock and the clock generated from the time-base
timer, and keeps operating while those clocks are being supplied. Therefore, in the operation
immediately after a peripheral function is started, an error of up to one cycle of the clock
source captured by that peripheral function will occur, depending on the output value of the
prescaler.
Figure 3.10-1 Clock Capture Error Occurring Immediately after a Peripheral Function Starts
Prescaler output
Start of peripheral function
Clock captured by
peripheral function
The prescaler count value affects the following peripheral functions:
• 8/16-bit composite timer
• 8/10-bit A/D converter
• 8/16-bit PPG
• 16-bit PPG timer
• 16-bit reload timer
• UART/SIO dedicated baud rate generator
MN702-00009-2v0-E
a peripheral function starts
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER 3 CLOCK CONTROLLER
3.10 Notes on Using Prescaler
Clock capture error
immediately after
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