Data Transmission unit has services those are used to read/write data to ECU /From ECU.
|S.No||Service Name||Service ID|
|1.||Read data By Identifier||0x22|
Some Important Services are explained below with the help of Request and Response.
Read Data By Identifier(RDBI) service request is sent by tester(Client) to read some data from ECU(Server). Tester use service ID 0x22 along with Data Identifier(DID) to read specific data from Server’s Memory. DIDs are unique number ,Dedicated to some specific operation. These DIDs are defined by manufacturer.
A. Request Format for Single DID data record:
Suppose Tester wants to read data for Data Identifier = 0xAA55 , then request format will be like this-
RESPONSE Format for Single DID data record:
Where D1….Dn is the data read from ECU corresponding to DID 0xAA55.
B. REQUEST Format for Multiple DID data record:
Suppose Tester wants to read data for DID1= 0xAA55 and DID2= 0xF001. then request format will be –
RESPONSE Format for Multiple DID data record:
Note: Data record D1 byte will be MSB.
As the name shows “Read memory by address” i.e. client will send address in request to read Data of requested address of ECU.
Request Format (16-bit server platform):
If Success then Response will be:
In case of error, response frame format will be:
For NRC follow the iso spec 14229(1).