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3 manageable items, 4 delayed execution, 3 manageable items 4.4 delayed execution – DekTec DTM-3237 DVB-S2 Receiver User Manual

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DTM-3237 – OEM DVB-S2 Receiver with DVB-ASI Output

User Manual

17

When an incorrect checksum is detected, the DTM-3237 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, the device

will ignore the data.
When a master starts reading from a device while there is no answer available (yet), the device will

reply with the value 0x00. The value 0x00 will be returned until an answer is available and the master

has initiated a new read transaction.
S and P are the standard I

2

C start and stop conditions.

Please refer to Appendix D for a communication example.

4.3 Manageable items

The tables in the sections below provide lists of variables that can be configured and/or monitored

using the USB, I

2

C or LVTTL serial control port interface. The ‘Access’ column indicates whether the

variable can be changed or not, according to the table below.

Access

Description

RO

Read only

WO

Write only

R/W

Read and/or write

R/Wusb

Read from all interfaces, write from USB only

NA

Not applicable

DE-XXX

Delayed execution (see §4.4 - Delayed execution)

4.4 Delayed execution

Most items are processed directly when the read or write command is received, which will immediately

result in an action on the device. In contract to these directly processed items, some items require

more processing time and therefor these actions are performed with a delay in a background thread.

Items which execution is delayed are marked with a “DE” (delayed execution) prefix in the access

column.
Items which execution is delayed can be monitored by the “Busy” item (category 0x01, setting 0x0C).

During the execution of these items, the “Busy” item is set and it is not possible to execute other “DE”

marked items. In case the “Busy” item is set and a “DE” marked command is received, the device will

return with a ‘B’ (busy) result in the Read/Write field of the DTM protocol frame structure.