Appendix d. communication example – DekTec DTM-3237 DVB-S2 Receiver User Manual
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DTM-3237 – OEM DVB-S2 Receiver with DVB-ASI Output
User Manual
35
Appendix D. Communication Example
In the examples below, grey areas in the timing diagrams are sent by the DTM-3237, while white
areas are sent by the master. The I
2
C address of the DTM-3237 in these examples is 0x60.
Serial write command on LVTTL serial control port interface or USB interface
Figure 5 shows the write command of the LNB enable at the tuner and demodulator settings (category
90, setting 9, index 0). All values are displayed as ASCII characters.
Figure 5: Write LNB enable in the tuner and demodulator settings
The command consists of the following parts:
Start character ‘STX’
Two hexadecimal address characters (“60”) (address doesn’t care, see §4.2.1)
Two hexadecimal category characters (“90”)
Two hexadecimal setting characters (“09”)
A write character ‘W’
Four hexadecimal index characters (“0000”)
Two hexadecimal data characters (“01”)
Two hexadecimal checksum characters (“50”, See Table 1)
Stop character ‘ETX’
Table 1: Checksum computation
Characters
ASCII value
6
0x36
0
0x30
9
0x39
0
0x30
0
0x30
9
0x39
W
0x57
0
0x30
0
0x30
0
0x30
0
0x30
0
0x30
1
0x31
Sum:
0x2B0
Checksum:
0x50
Serial read command on LVTTL serial control port interface or USB interface
Figure 6 shows the read command of the device type number (category 1, setting 5). The returned
data consists of 4 bytes (int32). All values are displayed as ASCII characters.