micrf507ymltr Micrel Semiconductor, micrf507ymltr Datasheet - Page 33

• Manufacturer Part Number: micrf507ymltr
• Description: 470mhz To 510mhz Low-power Fsk Transceiver With +10dbm Power Amplifier
• Manufacturer: Micrel Semiconductor

System Modes and Initialization
Start-up and Initialization
After supply voltage is applied to the MICRF507, a power
on reset period elapses during which it should be
considered to be in an unknown state. The microcontroller
should wait until power on reset is completed.
“Power-On Reset” subsection within the “Control (3-wire)
Interface” section.
writeable registers must be correctly initialized before
operation of the MICRF507. Write only non-zero values to
the M0, N0, M1, and N1 fields.
Modes of Operation
Mode Transitions
To go from power down mode to either receive or transmit
mode, the MICRF507 needs to go through the standby
mode first. This is to ensure that the crystal oscillator starts
up correctly. Once the crystal oscillator settles, the
MICRF507 can go to receive or transmit mode.
When the mode has been changed to Transmit or
Receive, or when the power amplifier has been enabled,
the synthesizer must be allowed to stabilize. See “Lock
Detect” section.
March 2010
Micrel, Inc.
Mode1
0
0
1
1
Mode0
0
1
0
1
Table 20. Main Mode Bits
Field Name
Transmit
Standby
Receive
OUTS
After power-on is completed, all 22
Mode
Power
State
down
Comments
Keeps register configuration
Only crystal oscillator
running
Full receive
Full transmit except PA
state
Number
of bits
Table 21. Register Bit Fields for System Functions
2
4
Reg2[3:0]
Reg0[2:1]
Location
of bits
See
Description
Main mode selection
Test pins output
33
When using VCO modulation; after MICRF507 has been
put in transmit mode, the microcontroller will tri-state the
driver connected to DATAIXO pin to leave that pin floating
until the microcontroller begins sending data. This is
because in transmit mode, the modulator is disabled while
the DATAIXO pin is floating (a weak voltage divider sets its
level at Vdd/2) in order to prevent a performance-
degrading transient when message transmission begins.
Below, “write to registers” means writing a complete
control word, or writing just to registers that need to
change.
Transition to transmit mode:
Transition to receive mode:
•
•
•
•
•
•
•
•
Write to registers, setting transmit mode, and other
changes as needed; set/keep PA off (to reduce
spurious emissions).
input.
Write to registers setting PA on (this requires
updating Register 0 only).
Wait for LD.
Enable the microcontroller’s pin as an output
driving DATAIXO and begin sending the transmit
bitstream.
After the last bit is transmitted return the
microcontroller’s pin to being an input.
Have
disabled.
Write to registers setting receive mode and other
changes as needed.
Wait for LD. Or, if desired, commence checking
the received bitstream for a valid message without
waiting.
the
microcontroller’s
Reference
Table 20
Table 28
This makes DATAIXO an
DATAIXO
M9999-032210-B
MICRF507
driver