Measurement Computing DAQFlex - Manual (Page 5)

DAQFlex Message-based Firmware Specification Message-based control transfers
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 The DEV component message "DEV:DATATYPE=ENABLED" specifies whether raw data is enabled or
disabled for returned data. When DEV:DATATYPE=ENABLED, the first byte indicates the data type
returned. Refer to the RawData Notes for more information.
 The amount of data transferred must be specified in the wLength field.
Message-based control transfers
Digital I/O Commands
Command Description bRequest Direction
StringMessage Send string messages to the device 0x80 In/Out
RawData Return raw data from the device 0x81 In
StringMessage
— SMBI string message
This command reads/writes the string message components of a device. The device stores the various
components and parameters to provide read back.
Output arguments
string char[64]; 64 character string including a NULL terminator.
Input arguments
None
Input response
string char[64]; 64 character response string including a NULL terminator.
Notes
 Invalid output strings result in a STALL to the USB Control Transfer, and the input response returns
"INVALID".
RawData — Raw data with SMBI
This command reads the RAW data from the last StringMessage sent to the device. Data is only
returned if the StringMessage has matching RAW data; otherwise a 0 length packet is returned.
Output arguments
N/A – output is not currently supported.
Input arguments
None
Input response
DATATYPE 0x03 – uint8
0x07 – uin16
0x09 – uint32
0x0A – float32
0xFF – Invalid
value This depends upon the StringMessage sent, but will have the form of
DATATYPE. Invalid StringMessage result in a 0 length packet, or if
DATATYPE is set to ENABLE, one byte reading 0xFF.