Filter
Top Products
Section 14 Realtime Clock
Page 700 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
Bit Bit Name
Initial
Value R/W Description
16 to 0 RFC[16:0] Undefined R/W Frequency comparison value
Sets the comparison value to generate operation clock
from the EXTAL clock frequency.
(1) Method for calculating "frequency comparison value".
1-Mbyte version
EXTAL clock frequency is dividable by 128-Hz
RFC[16:0] (EXTAL clock frequency) / 128 2
Note: EXTAL clock frequency must be less than 16.778 MHz in the 1-Mbyte version.
640-Kbyte version
EXTAL clock frequency is dividable by 128-Hz
RFC[18:0] (EXTAL clock frequency) / 128 2
Clear the SEL64 bit to 0 in this case.
EXTAL clock frequency is dividable by 64-Hz and not dividable by 128-Hz
RFC[18:0] (EXTAL clock frequency) / 64 2
Set the SEL64 bit to 1 in this case.
(2) Setting Example
Table 14.3 Setting Example
EXTAL Clock
Frequency
1-Mbyte Version 640-Kbyte Version
RFC Setting Value SEL64 Setting Value RFC Setting Value
10 MHz H'1312B 0 H'1312B
12 MHz H'16E34 0 H'16E34
15 MHz No setting possible 1 H'39385
16 MHz H'1E846 0 H'1E846