Table of Contents
Advertisement
Section 24 Flash Memory
(3)
Flash Program/Erase Frequency Parameter (FPEFEQ: General Register ER0 of CPU)
FPEFEQ sets the operating frequency of the CPU. The operating frequency available in this LSI
ranges from 8 MHz to 25 MHz.
Bit
Bit Name
31 to 16
F15 to F0
15 to 0
Rev. 1.00 May 09, 2008 Page 740 of 954
REJ09B0462-0100
Initial
Value
R/W
R/W
Description
Unused
These bits should be cleared to 0.
Frequency Set
These bits set the operating frequency of the CPU. The
setting value must be calculated as follows:
1. Round off the operating frequency expressed in MHz
unit at the third decimal place to make it into two
decimal places.
2. Multiply the rounded number by 100 and convert the
result into binary and write it to FPEFEQ (general
register ER0).
For example, when the operating frequency of the CPU
is 20.000 MHz, the setting value is as follows:
1. Round 20.000 off at the third decimal place as
20.00.
2. Convert 20.00 × 100 = 2000 into a binary number
and set B'0000 0111 1101 0000 (H'07D0) in ER0.
Advertisement
Table of Contents
