Laird LT2510 User Manual page 20

LT2510
Wireless Module
THEORY OF
OPERATION
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RSSI Output to PWM
A moving RSSI Average can be written to the PWM Output as a signal strength indicator. The output pin to use, the
threshold range for the RSSI and the RSSI Type reported can all be configured through EEPROM Addresses.
The PWM Output has a 315.077uS period. The duty cycle is set by the RSSI value recorded by the transceiver and the
RSSI Threshold High and RSSI Threshold Low values
RSSI Threshold High (EEPROM 0x65)
Is the upper limit of the recorded RSSI reading. RSSI Values reported above this value (strong signals) will report a
100% Duty Cycle on the PWM Output.
RSSI Threshold Low (EEPROM 0x66)
Is the lower limit of the recorded RSSI reading. RSSI Values reported below this value (weak signals) will report a 0%
Duty Cycle on the PWM Output.
To calculate the thresholds use the equation:
RSSI_Dec = (RSSI_dBm + 82) * 2 +128
Then convert this from Decimal to Hexadecimal notation.
Sleep Indicator (EEPROM 0x45, bit 6)
When enabled, GIO_1 will toggle Low during sleep and high when the module is awake.
Sniff Permit (EEPROM 0x45, bit 0)
Sniff Permit will allow a radio to receive a data packet from another radio on the network regardless of the
Destination MAC Address in the packet. This allows an OEM to create a Sniffer for all network traffic. Sniff Permit
would need to be enabled on the transmitting radio, to grant it's permission to be heard. Sniff Report and Sniff
Permit would need to be enabled on the sniffer radio, to cause it to send sniffed packets out the serial port.
System ID (EEPROM 0x76)
System ID is similar to a password character or network number and makes network eavesdropping more difficult.
A receiving transceiver will not go in range of or communicate with another transceiver on a different System ID.
System ID can be ignored on a Client by enabling Auto System ID
Transmit Retries (EEPROM 0x4C)
When transmitting addressed packets, the RF packet is sent out to the receiver designated by its destination address.
Transmit Retries is used to increase the odds of successful delivery to the intended receiver. Transparent to the OEM
host, the transmitter will send the RF packet to the intended receiver. If the receiver receives the packet free of errors,
it will send the transmitter an acknowledgement. If the transmitter does not receive this acknowledgement, it will
assume the packet was never received and retry the packet. This will continue until the packet is successfully received
or the transmitter exhausts all of its retries. The received packet will only be sent to the OEM host if and when it is
received free of errors.
Note: Setting to 0 is equal to 256.
Unicast Only (EEPROM 0xC1, bit 3)
To prohibit transceivers from receiving broadcast packets, Unicast Only can be enabled. Unicast Only restricts the
transceiver to only receive addressed packets.
Vendor ID
The Vendor ID, like the System ID, can be used to uniquely identify a network. Radios with the Vendor ID set, will
only communicate with other radios with the same set Vendor ID.
The Vendor ID is a protected EEPROM parameter and it's value cannot be read. It can only be written once. OEMs
should be aware that improperly setting the Vendor ID can cause communication issues. Setting the Vendor ID to an
unknown setting will effectively render the radio unable to communicate in a network.
Note: The Vendor ID is a one-time write parameter and it cannot be read.
9600 Boot Option (EEPROM 0x57, bit 0)
When enabled, 9600 Boot Option causes the 9600 pin to be ignored on cold boot (power-up) and brown-out
conditions. Therefore, the 9600 pin is only observed on warm boots (reset pin toggled). This can be helpful so that
brown-out conditions don't cause the baud rate to change if the 9600 pin happens to be Low at the time. When
9600 Boot Option is disabled, the 9600 pin will be used for warm and cold boots as well as brown-out conditions.
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