Datasheet
Section 21 Flash Memory 
R01UH0310EJ0500 Rev. 5.00    Page 1103 of 1384 
Sep 25, 2012     
H8S/2426, H8S/2426R, H8S/2424 Group 
(3)  Communications Protocol 
After adjustment of the bit rate, the protocol for communications between the host and the boot 
program is as shown below. 
1.  One-byte commands and one-byte responses 
These commands and responses are comprised of a single byte. These are consists of the 
inquiries and the ACK for successful completion. 
2.  n-byte commands or n-byte responses 
These commands and responses are comprised of n bytes of data. These are selections and 
responses to inquiries. 
The amount of programming data is not included under this heading because it is determined 
in another command. 
3. Error response 
The error response is a response to inquiries. It consists of an error response and an error code 
and comes two bytes. 
4.  Programming of 128 bytes 
The size is not specified in commands. The size of n is indicated in response to the 
programming unit inquiry. 
5. Memory read response 
This response consists of 4 bytes of data. 










