MRF49XA-I/ST Microchip Technology, MRF49XA-I/ST Datasheet - Page 68

• Manufacturer Part Number: MRF49XA-I/ST
• Description: IC RF TXRX 433/868/915 16-TSSOP
• Manufacturer: Microchip Technology

Specifications of MRF49XA-I/ST

• Package / Case: 16-TSSOP
• Frequency: 433MHz, 868MHz, 915MHz
• Data Rate - Maximum: 256kbps
• Modulation Or Protocol: FHSS, FSK
• Applications: Home / Industrial Automation, Remote Access, Security Alarms
• Power - Output: 7dbm
• Sensitivity: -110dBm
• Voltage - Supply: 2.2 V ~ 3.8 V
• Current - Receiving: 11mA
• Current - Transmitting: 15mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Number Of Receivers: 1
• Number Of Transmitters: 2
• Wireless Frequency: 433 MHz to 915 MHz
• Output Power: + 7 dBm
• Operating Supply Voltage: 2.5 V, 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Modulation: FHSS, FSK
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 579-MRF49XA-1/ST

The device transmit sequence should be performed as
follows:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10. The next high-to-low transition on the IRO line
11. Turn off the transmitter by setting the bit,
12. Clearing the TXDEN bit clears the register
TABLE 3-3:
DS70590B-page 66
MRF49XA
Transmit
Mode
Enable the TX register by setting TXDEN = 1.
The TX register is automatically filled with
0xAAAA, which can be used to generate
preamble.
Enable the transmitter by setting TXCEN = 1.
The synthesizer and the PLL turns on, calibrates
itself and the power amplifier is automatically
enabled.
The TX data transmission starts.
On completion of byte transmission, the IRO pin
goes high and the SDO pin goes low simultane-
ously. The IRO pulse shows that the first 8 bits
(the first byte by default, 0xAA) have been
transmitted. There are still 8 bits in the transmit
register.
The microcontroller recognizes the interrupt and
writes a data byte to the TXBREG.
Repeat steps 6 and 7 until the last data byte is
reached.
Using the same method, transmit a dummy byte.
The value of this dummy byte can be anything.
(or low-to-high on the SDO pin) shows that the
transmission of the data bytes has ended. The
dummy byte is still in the TX latch.
TXCEN = 0. This event probably happens while
the dummy byte is being transmitted. Since the
dummy byte contains no useful information, this
corruption will not cause any problem.
underrun interrupt. The IRO pin goes high and
the SDO pin goes low.
TXDEN = 0
TXDEN = 1
Bit Setting
TRANSMIT PIN FUNCTION
Internal TX Data register disabled
Internal TX Data register enabled
Function
VS
Preliminary
. OPERATION MODE
The transmit sequence is illustrated in Figure 3-16. For
details on transmit pin function configuration, see
Table 3-3. The TXDEN bit is in the GENCREG register
and enables the Transmit Data register.
The transmit sequence can be performed without send-
ing a dummy byte (step 1), but after loading the last
data byte to the transmit register, the PA turn off should
be delayed for at least 16 bits time. The microcontroller
clock source (if the clock is not supplied by the trans-
ceiver) should be stable enough over temperature and
voltage ranges to ensure this minimum delay under all
operating circumstances.
When the dummy byte is used, the whole process is
driven by interrupts. Changing the TX data rate has no
effect on the algorithm and no accurate delay measure-
ment is needed. Figure 3-17 shows the multi-byte
transmit write sequence.
The registers associated with transmission are:
• STSREG (see Register 2-1)
• GENCREG (see Register 2-2)
• TXCREG (see Register 2-4)
• TXBREG (see Register 2-5)
• PMCREG (see Register 2-13)
(TX Data register can be
TX data input
FSEL input
accessed)
Pin 6
© 2009 Microchip Technology Inc.
Not used
Pin 7