SX1239IMLTRT Semtech, SX1239IMLTRT Datasheet - Page 39

• Manufacturer Part Number: SX1239IMLTRT
• Description: IC, RF RECEIVER, 1.02GHz, QFN-24
• Manufacturer: Semtech

Specifications of SX1239IMLTRT

• Applications: Wireless Sensor Networks, Automated Meter Reading, Home And Building Automation
• Receiving Current: 16mA
• Data Rate: 300Kbps
• Modulation Type: FSK, OOK
• Sensitivity Dbm: -120dBm
• Rohs Compliant: Yes
• Rf Ic Case Style: QFN
• No. Of Pins: 24
• Sensitivity (dbm): -120dBm
• Supply Voltage Range: 1.8V To 3.6V
• Operating Temperature Range: -40°C To +85°C
• Lead Free Status / Rohs Status: Supplier Unconfirmed

The frame ends when NSS goes high. The next frame must start with an address byte. The SINGLE access mode is
actually a special case of FIFO / BURST mode with only 1 data byte transferred.
During the write access, the byte transferred from the slave to the master on the MISO line is the value of the written
register before the write operation.
5.2.2. FIFO
5.2.2.1. Overview and Shift Register (SR)
In packet mode of operation, data that has been received is stored in a configurable FIFO (First In First Out) device. It is
accessed via the SPI interface and provides several interrupts for transfer management.
The FIFO is 1 byte wide hence it only performs byte (parallel) operations, whereas the demodulator functions serially. A
shift register is therefore employed to interface the two devices. In Rx the shift register gets bit by bit data from the
demodulator and writes them byte by byte to the FIFO. This is illustrated in Figure 22.
Note
5.2.2.2. Size
The FIFO size is fixed to 66 bytes.
5.2.2.3. Interrupt Sources and Flags
Rev 3 - Jan 2011
ADVANCED COMMUNICATIONS & SENSING
FifoNotEmpty: FifoNotEmpty interrupt source is low when byte 0, i.e. whole FIFO, is empty. Otherwise it is high. Note
that when retrieving data from the FIFO, FifoNotEmpty is updated on NSS falling edge, i.e. when FifoNotEmpty is
updated to low state the currently started read operation must be completed. In other words, FifoNotEmpty state must
be checked after each read operation for a decision on the next one (FifoNotEmpty = 1: more byte(s) to read;
FifoNotEmpty = 0: no more byte to read).
FifoFull: Fifofull interrupt source is high when the last FIFO byte, i.e. the whole FIFO, is full. Otherwise it is low.
FifoOverrunFlag: FifoOverrunFlag is set when a new byte is written by the SR while the FIFO is already full. Data is lost
and the flag should be cleared by writing a 1, note that the FIFO will also be cleared.
FifoLevel: Threshold can be programmed by FifoThreshold in RegFifoThresh. Its behavior is illustrated in figure below.
When switching to Sleep mode, the FIFO can only be used once the ModeReady flag is set (quasi immediate from
all modes)
Rx Data
Figure 22. FIFO and Shift Register (SR)
1
MSB
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SR (8bits)
byte1
byte0
8
LSB
FIFO
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