DekTec DTM-3237 DVB-S2 Receiver - Manual (Page 14)

DTM-3237 – OEM DVB-S2 Receiver with DVB-ASI Output
User Manual
14
4. Device Configuration and Monitoring
4.1 Control interfaces
The DTM-3237 can be configured and monitored using USB, I 2 C and LVTTL serial control port. The
I 2 C address and LVTTL serial control port baud rate can only be configured through the USB interface,
e.g. with Dtm3237Util. It is not required to select between the interface of your choice (USB, I 2 C and
LVTTL serial control port): The DTM-3237 will automatically use the interface on which it detects
activity.
 The default I 2 C address is 0x60.
 The default LVTTL serial control port baud rate is 9600.
The USB interface is implemented as USB to serial emulator and therefor the USB and LVTTL serial
control port protocol are the same. The baud rate for the USB serial emulator is 256000.
All control interfaces use the same command and response protocol that is described below.
4.2 Command protocol
Commands and responses are wrapped into a frame structure that contains address, category, setting,
read/write, index and data (optional). The DTM-3237 accepts uppercase and lowercase characters,
but will always respond in uppercase.
4.2.1 Command protocol on USB and LVTTL serial control port
Field Format Description
Start ASCII character
STX (0x02)
ASCII “start of text” character
Address 2 hex digits 2 8-bit address 3
Category 2 hex digits Selects a “category” of settings
Setting 2 hex digits Selects a setting within the selected category
Read/Write ASCII character
‘R’ or ‘W’
‘R’ for read and ‘W’ for write
Index 4 hex digits Provides an extra index parameter, e.g. to indicate the
channel number 4
Data n hex digits / n
ASCII characters
The data written or read. The data length is variable for
each setting. In case of a write operation, the data is a
(negative) acknowledgement
Checksum 2 hex digits This is the least significant byte of the two’s complement 5
sum of all characters in the message, excluding the STX and
ETX characters and the checksum itself
End ASCII character
ETX (0x03)
2 Hex digits are the ASCII characters 0…9 and A…F, concatenated to form a single hexadecimal value.
3 The DTM-3237 only supports LVTTL serial control port and USB, so no address is necessary and therefor this value
doesn’t care.
4 The DTM-3237 supports a single channel only, so when index is used as a channel number, it’s always 0.
5 Invert all bits and add one.