Datasheet

Section 17 ROM
Rev.7.00 Feb. 14, 2007 page 765 of 1108
REJ09B0089-0700
(11) New Bit-Rate Selection
The boot program will set a new bit rate and return the new bit rate.
This selection should be sent after sending the clock mode selection command.
Command H'3F Size Bit rate Input frequency
Number of
multiplication ratios
Multiplication
ratio 1
Multiplication
ratio 2
SUM
• Command, H'3F, (1 byte): Selection of new bit rate
• Size (1 byte): The number of bytes that represents the bit rate, input frequency, number of
multiplication ratios, and multiplication ratio
• Bit rate (2 bytes): New bit rate
One hundredth of the value (e.g. when the value is 19200 bps, the bit rate is H'00C0, which is
D'192.)
• Input frequency (2 bytes): Frequency of the clock input to the boot program
This is valid to the hundredths place and represents the value in MHz multiplied by 100. (e.g.
when the value is 20.00 MHz, the input frequency is H'07D0 (= D'2000).)
• Number of multiplication ratios (1 byte): The number of multiplication ratios to which the
device can be set. Normally the value is two: main operating frequency and peripheral module
operating frequency.
• Multiplication ratio 1 (1 byte): The value of multiplication or division ratios for the main
operating frequency
⎯ Multiplication ratio (1 byte): The value of the multiplication ratio (e.g. when the clock
frequency is multiplied by four, the multiplication ratio will be H'04. With this LSI it
should be set to H'01.)
⎯ Division ratio: The inverse of the division ratio, as a negative number (e.g. when the clock
frequency is divided by two, the value of division ratio will be H'FE. H'FE = D'-2. With
this LSI it should be set to H'01.)
• Multiplication ratio 2 (1 byte): The value of multiplication or division ratios for the peripheral
frequency
⎯ Multiplication ratio (1 byte): The value of the multiplication ratio (e.g. when the clock
frequency is multiplied by four, the multiplication ratio will be H'04. With this LSI it
should be set to H'01.)
⎯ Division ratio: The inverse of the division ratio, as a negative number (e.g. when the clock
is divided by two, the value of division ratio will be H'FE. H'FE = D'-2. With this LSI it
should be set to H'01.)
• SUM (1 byte): Checksum