HD64F3687GHV Datasheet, PDF (116/566 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 5 Clock Pulse Generator
LSI operates on
external clock
Start
(LSI operates on external clock)
Write 0 to OSCBAKE in CKCSR
[1] When 0 is written to the OSCSEL bit, this LSI
switches from the external clock to the on-chip
oscillator clock after a φ stop duration. The φ halt
duration here is the duration while the φ_RC clock
rises seven times after the OSCSEL bit becomes
0.
[2] Writing 0 to PMRC0 disables the external
oscillation input.
Write 1 to CKSWIE in CKCSR
if necessary
Write 0 to OSCSEL in CKCSR [1]
LSI operates on
on-chip oscillator clock
When CKSWIE = 1
Exception handling
for clock switching
Write 0 to PMRC0 in CKCSR
[2]
if necessary
LSI operates on
on-chip oscillator clock
Figure 5.5 Flowchart of Clock Switching with Backup Function Disabled (2)
(From External Clock to On-Chip Oscillator Clock)
Rev. 3.00 Sep. 10, 2007 Page 82 of 528
REJ09B0216-0300