General Specification Electrical Function gmw3110 General Motors Local Area Network Enhanced Diagnostic Test Mode Specification

9.3.2.4.6 Service $34 - Request to Download Data Block. 
Receipt of a valid request for this service causes 
an SPS_TYPE_A ECU to transfer program control back to the boot software. Transferring control back to the 
boot software allows the ECU to allocate the necessary resources to support being reprogrammed. Examples 
of resource allocation include a larger buffer for the Network layer and use of a smaller STmin value to 
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GM WORLDWIDE ENGINEERING STANDARDS 
GMW3110 
© Copyright 2010 General Motors All Rights Reserved 
February 2010 
Page 258 of 336 
optimize data transfer. The ECU shall support in the boot software the same dataFormatIdentifier values as 
supported by the operational software. 
9.3.2.4.6.1 Pseudo Code 
(Refer to the data dictionary of the application implementation of this service for 
variable definitions.) 
BEGINFUNCTION Boot_34_Msg_Recvd() 
IF ( (dataFormatIdentifier is invalid) OR ((dataFormatIdentifier != $00) AND (unCompressedMemory size is 
invalid)) ) THEN 
send Negative Response($7F $34 $12) /* Invalid Format */ 
ELSE 
IF ( (programming_mode_active = NO) OR (a software or calibration module download is in progress)) 
THEN 
send Negative Response ($7F $34 $22) /* for conditionsNotCorrect */ 
ELSE 
IF (more than P2
C
ms is needed to process this request) THEN 
send Negative Response ($7F $34 $78) /* RequestCorrectlyReceived-ResponsePending */ 
ENDIF 
/* at this time the module shall do whatever is necessary to prepare for a DataTransfer service 
request. */ 
IF (DTC for Flash or EEPROM checksum failure is set) THEN 
send Negative Response ($7F $74 $99) /*ReadyForDownload-DTCStored */ 
ELSE 
send ($74) response message 
TransferData_Allowed 

YES 
ENDIF 
ENDIF 
ENDFUNCTION