HD64F2168 Datasheet, PDF (671/874 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer

(2) Programming/Erasing Initialization
The on-chip programming/erasing program to be downloaded includes the initialization program.
The specified period pulse must be applied when programming or erasing. The specified pulse
width is made by the method in which wait loop is configured by the CPU instruction. The
operating frequency of the CPU must be set.
The initial program is set as a parameter of the programming/erasing program which has
downloaded these settings.
(a) Flash programming/erasing frequency parameter (FPEFEQ: general register ER0 of CPU)
This parameter sets the operating frequency of the CPU. The settable range of the operating
frequency in this LSI is 5 to 33 MHz.
Initial
Bit
Bit Name Value R/W
31 to 16 


15 to 0 F15 to F0 
R/W
Description
Unused
This bit should be cleared to 0.
Frequency Set
Set the operating frequency of the CPU. With the PLL
multiplication function, set the frequency multiplied. The
setting value must be calculated as the following
methods.
1. The operating frequency which is shown in MHz units
must be rounded in a number to three decimal places
and be shown in a number of two decimal places.
2. The value multiplied by 100 is converted to the binary
digit and is written to the FPEFEQ parameter
(general register ER0).
For example, when the operating frequency of the CPU
is 33.000 MHz, the value is as follows.
1. The number to three decimal places of 33.000 is
rounded and the value is thus 33.00.
2. The formula that 33.00 × 100 = 3300 is converted to
the binary digit and B'0000,1100,1110,0100
(H'0CE4) is set to ER0.
Rev. 3.00, 03/04, page 631 of 830