MRF49XA Datasheet, PDF (69/102 Pages) Microchip Technology – ISM Band Sub-GHz RF Transceiver

FIGURE 3-16:
TX REGISTER USAGE
Enabling the transmitter preloads the TX latch with
0xAAAA
MRF49XA
Do not switch the TXCEN off here, because the TX
Byte 1 is not transmitted out, it is only stored in the
internal register
SPI
Commands
(CS, SCK, SDI)
GENCREG
TXDEN = 1
PMCREG
TXCEN = 1
TXCEN
TX Latch
TX Byte 1
TX Latch
Dummy
TX Byte
PMCREG
TXCEN = 0
GENCREG
TXDEN = 0
Enable
Synthesizer/PA
TX Data
IRO
Synt.
Ttx_xtal_on⁽¹⁾
PA
0xAA
0xAA
TX Byte1
Fraction of the dummy byte
SDO⁽²⁾
Note 1: Ttx_xtal_on is the start-up time of PLL + PA with a running crystal oscillator.
2: SDO is a tri-state of CS.
FIGURE 3-17:
CS
MULTIPLE BYTE WRITE WITH TRANSMIT REGISTER
SCK
SDI
Transmit Register Write
TX BYTE 1
TX BYTE 2
SDO
(Register interrupt in TX mode*)
* The device is in Transmit (TX) mode when the RXCEN bit is cleared using the PMCREG.
TX BYTE n
© 2009 Microchip Technology Inc.
Preliminary
DS70590B-page 67