Appendix D. Communication Example - DekTec DTM-3237B User Manual

DTM-3237B – DVB-S2X Receiver with DVB-ASI Output
User Manual

Appendix D. Communication Example

In the examples below, grey areas in the timing diagrams are sent by the DTM-3237B, while white
areas are sent by the master. The I
Serial write command on 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.
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'
Serial read command on 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.
2 C address of the DTM-3237B in these examples is 0x60.
Figure 5: Write LNB enable in the tuner and demodulator settings
Table 1: Checksum computation
Characters
6
0
9
0
0
9
W
0
0
0
0
0
1
Sum:
Checksum:
ASCII value
0x36
0x30
0x39
0x30
0x30
0x39
0x57
0x30
0x30
0x30
0x30
0x30
0x31
0x2B0
0x50
42