r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 1193

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

24.5
24.5.1
1. The following points should be noted since the frequency of φ changes according to the
2. All the on-chip peripheral modules operate on the φ. Therefore, note that the time processing
3. Note that the frequency of φ will be changed when setting PLLCR while executing the external
24.5.2
Since various characteristics related to the resonator are closely linked to the user’s board design,
thorough evaluation is necessary on the user’s part, using the resonator connection examples
shown in this section as a guide. As the parameters for the oscillation circuit will depend on the
floating capacitance of the resonator and the user board, the parameters should be determined in
consultation with the resonator manufacturer. The design must ensure that a voltage exceeding the
maximum rating is not applied to the resonator pin.
settings of PLLCR.
Select a clock division ratio that is within the operation guaranteed range of clock cycle time
tcyc shown in the AC timing of the Electrical Characteristics. In other words, φ must be set to
a value between 8 MHz (minimum) and 33 MHz (maximum). The setting of φ must not be less
than 8 MHz or greater than 33 MHz.
of modules such as a timer and SCI differ before and after changing the clock division ratio. In
addition, wait time for clearing software standby mode differs by changing the clock division
ratio. See the description, Setting Oscillation Stabilization Time after Clearing Software
Standby Mode in section 25.2.3, Software Standby Mode, for details.
bus cycle with the write-data-buffer function.
Usage Notes
Notes on Clock Pulse Generator
Notes on Resonator
Rev. 1.00 Sep. 19, 2008 Page 1163 of 1342
Section 24 Clock Pulse Generator
REJ09B0467-0100