Datasheet

Section 22 Flash Memory
Page 1184 of 1408 R01UH0309EJ0500 Rev. 5.00
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
(j) 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 19,200 bps, the bit rate is H'00C0, which is
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 64 MHz, the input frequency is H'1900 (= 6400)).
• Number of multiplication ratios (1 byte): The number of multiplication ratios to which the
device can be set.
• 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.)
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 = [-2])
• 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.)
(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 = [-2])