Patent ID: 7817654

Claim:
A test device for a motor vehicle bus, the test device comprising: a bus controller for the transmission and reception of bus messages, the bus controller having a message memory for offering transmission data for bus messages, the message memory having a storage capacity for one bus message sequence with bus messages to be transmitted within a single transmission cycle or a transmission cycle sequence; an intermediate memory for the storage of transmission data for bus messages with a larger storage capacity than the message memory; and a transmission preparing means for reading the transmission data from the intermediate memory and for writing, preceding a reading of the bus controller, to the message memory of the bus controller so that the bus message sequence is expanded by additional bus messages, which are transmitted by the bus controller within the transmission cycle or the transmission cycle sequence on the motor vehicle bus wherein the transmission preparing means comprises a head preparing means for writing head data to the message memory and a user data preparing means for writing user data to the message memory, the head data being provided for the production of message heads of the bus message and the user data being provided for the user data respectively following the message heads, of the bus messages, the head preparing means writing the message heads, before the user data preparing means writes the associated user data to the message memory, so that the user data preparing means can modify the user data during an locked phase, in which the bus controller in advance blocks the writing of message heads to the message memory prior to the transmission of a respective bus message.