DekTec DTM-3237 DVB-S2 Receiver - Manual (Page 35)

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.