Normally every field is displayed in the Decode Pane. The special IN_SUMMARY clause prompts the protocol analyzer to display it in the Summary Pane as well. The keyword IN_SUMMARY is followed by the name of the column in which the value should be shown. Referencing a column in this way suffices to create it. The name is followed by a number that specifies the default width of the column in pixels.
We will enhance our FP decoder by putting the checksum and command_code fields in the Summary pane. The IN_SUMMARY keyword appears right before the label. The resulting field statements are:
FIELD command_code (Fixed 1 Byte) (Hex) IN_SUMMARY "Command/Response" 150 "Command"
FIELD checksum (Fixed 1 Byte) (Hex) IN_SUMMARY "C'sum" 40 "Checksum" VERIFY (FPChecksum)
Our decode of the Set Actuator command now looks like this (changes are in bold):
"Fictitious Protocol" 0x7f000000
DECODE
FIELD command_code (Fixed 1 Byte) (Hex) IN_SUMMARY "Command/Response" 150 "Command"
FIELD actuator_number (Fixed 1 Byte) (Decimal) "Actuator Number" VERIFY (FieldIsBetween 1 32)
FIELD actuator_value (Fixed 2 Bytes) (Decimal) "Value to set"
FIELD checksum (Fixed 1 Byte) (Hex) IN_SUMMARY "C'sum" 40 "Checksum" VERIFY (FPChecksum)
END_MAIN_PATH
You can put the value of more than one field into the same Summary pane column. For example, the name of the command_code column is "Command/Response", which implies that somewhere there is a response_code field, which also puts its value in the Command/Response column. All you need to do is reference the same column name in the second field. For example:
FIELD response_code (Fixed 1 Byte) (Hex) IN_SUMMARY "Command/Response" 150 "Response"
The advantage of doing this is that you can easily see a command followed by its response in the Summary pane. In the case of our Fictitious Protocol, where a central is not supposed to talk unless instructed to by the central, cases where a central speaks out of turn or a central has to ask something twice jump out. Here's a fragment of the Summary pane illustrating this:
