Renesas H8S/2100 Series Hardware Manual page 809

(k) 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
Number of division
ratios
SUM
• Command, H'3F, (one byte): Selection of new bit rate
• Size (one byte): The total number of bytes that represents the bit rate, input frequency, number
of division ratios, and division ratio
• Bit rate (two bytes): New bit rate
One hundredth of the value (e.g. when the value is 19200 bps, it will be 192, which is H'00C0.)
• Input frequency (two 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, it will be 2000, which is H'07D0.)
• Number of division ratios (one byte): The number of division ratios to which the device can be
set.
There are usually two division ratios, which are the main and peripheral module operating
frequencies.
• Division ratio 1 (one byte): The value of division ratios for the main operating frequency
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)
• Division ratio 2 (one byte): The value of division ratios for the peripheral frequency
(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)
• SUM (one byte): Checksum
Response H'06
• Response, H'06, (one byte): Response to selection of a new bit rate
When it is possible to set the bit rate, the response will be ACK.
Error Response H'BF
• Error response, H'BF, (one byte): Error response to selection of new bit rate
Size
Division ratio
1
ERROR
Bit rate Input frequency
Division ratio
2
Rev. 1.00 May 09, 2008 Page 783 of 954
Section 24 Flash Memory
REJ09B0462-0100