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

DynamicPidStructArray[] 
This is an array of structures that contain the data needed to support dynamic 
PIDs. Each structure contains the following information: 

PidNumber - The dynamic PID number. This is hardcoded in the structure 
and is not modified by this service. The DynamicPidStructArray contains an 
array element (which is a structure) for each dynamic PID that the ECU 
supports. 

MemAddr - The starting memory address assigned to this dynamic PID via 
this service. 

Length - The number of bytes to be transmitted starting with the contents of 
MemAddr when this PID is requested. 
The pseudo code uses the following convention to access an element of the 
structure: 
DynamicPidStructArray[0]. PidNumber would be the PID number of the first 
dynamic PID structure in the array. 
N/A 
NumArrayElements 
This is a local variable that contains the number of elements in the 
DynamicPidStructArray. 
ECU dependent 
Index 
This is a local variable used in the pseudo code to index into the 
DynamicPidStructArray. 
0 to 
(NumArrayElements -1) 
ValidIndex 
This is a local variable used in the pseudo code to record the value of Index 
when the PID in the request message matches the PidNumber element of the 
DynamicPidStructArray. 
0 to NumArrayElements 
8.11.6.2 Node Interface Pseudo Code. 
Powerup States: 
None 
Each time a $2D message is received, the following logic is executed: 
BEGINFUNCTION Serv_2D_Msg_Recvd() 
Bad_Address 

FALSE 
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ValidIndex 

NumArrayElements 
IF (message_data_length != (4 + numAddressBytes
)
) THEN
send Negative Response ($7F $2D $12) /*Subfunction Not Supported or Invalid Format */ 
ELSE 
IF (the response cannot be sent within P2
C
ms) THEN 
send Negative Response ($7F $2D $78) /*RequestCorrectlyReceived-ResponsePending */ 
ENDIF 
FOR (Index 

$00 TO (NumArrayElements - 1) BY $01) 
IF (parameterIdentifier = DynamicPidStructArray[Index].PidNumber) 
ValidIndex 

Index 
Index 

NumArrayElements /* to exit for loop */ 
ENDIF 
ENDFOR 
IF ((ValidIndex = NumArrayElements) OR (memorySize = 0d) OR (memorySize > 7)) THEN 
send Negative Response ($7F $2D $31) /*Request Out Of Range */ 
ELSE 
\* Check whether any memory address in the requested interval is protected, restricted (by Security 
Status) or invalid*/ 
FOR (Memory_Address 

memoryAddress TO (memoryAddress + memorySize- $01) BY $01) 
IF ( ((Memory_Address is secure) AND (Security_Access_Unlocked = FALSE)) OR
(Memory_Address is restricted) OR
(Memory_Address is Invalid) ) THEN 
Bad_Address 

TRUE 
Memory_Address 

(memoryAddress + memorySize) /* exit for loop */ 
ENDIF 
ENDFOR 
IF (Bad_Address = TRUE) THEN 
send Negative Response ($7F $2D $31) /*Request Out Of Range */ 
ELSE
DynamicPidStructArray[ValidIndex].MemAddr 

memoryAddress 
DynamicPidStructArray[ValidIndex].Length 

memorySize 
/* send positive response message */ 
send ($6D $PID_B1 $PID_B2)
ENDIF 
ENDIF 
ENDIF 
ENDFUNCTION 
Note:
The pseudo code above assumes the data contained within the dynamic PID structure is used by the 
services that provide PID data when these services build a response message.