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DTM-3200 – OEM Ethernet TSoIP Converter
User Manual
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Figure 7 below shows the sequence to send a command over I
C to the DTM-3200. If the command
is a read-command, the data may be omitted. If the category does not require an index, the index
must be omitted.
Figure 7. Command (upper sequence) and response (lower) sequence for I
C
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When an incorrect checksum is detected, the DTM-3200 will not return an answer. When protocol
errors are detected, e.g. a combination of a valid category with an invalid setting, the R/W byte of
the reply is replaced by the ASCII character 'E' and the data is removed from the message.
When a master starts writing to a device while the previous command is still being executed, this
device replies with a NACK.
When a master starts reading from a device and there is no answer available (yet), the device wil
reply with the value 0x00. The value 0x00 will be returned until an answer is available a
master has initiated a new read transaction.
Note: In DTM-3200 package versions v1.3 and lower, in the case mentioned above, the d
replies with a NACK instead of the value 0x00.
S and P are the standard I
2
C start and stop conditions. A repeated start condition can be used at all
times to concatenate multiple I
2
C read / write actions.
4.3 Manageable items
The tables in this section provide lists of variables that can be configured and/or monitored using
the I
2
C or RS-232/485/422 interface. The 'Access' column indicates whether the variable is Read
Only (RO), Write Only (WO), Read/Write (R/W) or not applicable (n.a.).
When, in the 'Access' column, the text "(V)" is written after the access type, the variable can be s
either in a volatile or non-volatile manner, depending on the 'Volatile Storage' setting (ca
0x02, setting 0x03). The volatility of the variables without "(V)" cannot be controlled.
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