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UM2241
Configuring the
ST75MM
DocID030767 Rev 1
23/26
4
Configuring the ST75MM
Only the four MIB objects detailed below need to be programmed/monitored to ensure
correct operation as receiver-only in the CENELEC 132.5 kHz band.
4.1
PHY configuration (MIB index 2)
In order to configure the ST75MM modem to work as a single channel receiver in the
CENELEC 132.5 kHz band the MIB object 2 shall be programmed with the following string:
{0x31, 0x95, 0x0A, 0x3B, 0x58, 0x9B}
Corresponding to the following configuration (selected values are in
bold
).
Table 17: PHY configuration values for CENELEC 132.5 kHz operations
Byte
Field
Bit
Sub-field
Description and values
0
General
settings
0
Current control
0: current control disabled
1: current control enabled
1
Zero crossing
0: next transmitted frame will start immediately
1: next transmitted frame will start at the next zero
crossing event
2
RX channel
0: single channel operations (only high channel)
1: dual channel operations
3
TX channel
0: transmit on high channel
1: transmit on low channel
4-
5
Frequency pair
0, 1, 2: reserved
3: custom frequency (see MIB 23 for channel
frequencies)
6
BU enable
0: band in use detector not enabled
1: band in use detector enabled
7
CSMA enable
0: CSMA not enabled
1: CSMA enabled
1
0-
4
TX gain
Gain, in dB, applied in transmission, default is 21 dB
(TX gain = 21)
5-
7
TX modulation
Modulation used in transmission:
0 to 3: reserved
4: BPSK coded
5: QPSK coded
6 to 7: reserved
2
0-
1
PSK preamble
0:16 bits preamble
1: 24 bits preamble
2: 32 bits preamble
3: 40 bits preamble
2
RX low
channel
Receiving mode for lower channel
0: FSK modulation
1: any PSK modulation