CH Tech EM405D - Manual (Page 23)

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The defaults that are restored using the above procedure are those set by the manufacturer of
the Ethernet device and not by C&H Technologies, Inc. The default settings of the carrier as
received from the factory at C&H are different in several key areas. The user must manually
return these settings to the default as set by C&H in order for the carrier to operate properly.
Refer to APPENDIX C or details on the factory default settings as received from C&H
Technologies, Inc.
4.3 COMMUNICATING WITH THE CARRIER AND M-MODULES
The EM405D uses a simple binary command structure to communicate with the host software.
The commands allow the user to either write or read registers residing on the EM405D or on
each M-module. By writing registers residing on the EM405D, the user can identify the module,
perform device configuration, and receive status. The registers residing on each M-module are
specific to the particular M-module. Refer to the M-module’s documentation for register details.
Each command consists of a command-id byte, a module number on which the command is to be
executed and parameters, if required. The commands are listed in Table I. Details of each
command are found throughout the rest of this section.
Table I. Command Summary
Binary
Command-id
Function
0x20 Write Data
0x30 Read Data
0x40 Block Write
0x50 Block Read
4.3.1 Error Handling
Each command will return a status code as the last byte returned. This status code will indicate
whether the command completed successfully or whether an error occurred while the EM405D
was performing the command. Table II shows a list of potential status codes that may be
returned.
Table II. Status Code (SC)
Value
Meaning
0x00 Successful
0x01 Invalid Command
0x02 Invalid Parameter
0x03 Module did not respond*
* Note: Applies to M-module requests only.