RTX-24EM
User guide
The technical characteristics can change without notice. AUR°EL S.p.A doesn’t assume the responsibility to the damages caused by an improper use of the device.
AUR°EL S.p.A.
Via Foro dei Tigli, 4 - 47015 Modigliana (FC) – ITALY 12/11/2019 - Rev. B
Tel.: +390546941124 – Fax: +390546941660 Page 8
http://www.aurel.it
5.2.1.1
In Communication mode:
The
TXFIFO
can be written at any time by the host microcontroller. When the SPI command
Send_TXFIFO
is
activated, the internal microcontroller will transmit all the content of the
TXFIFO
(or, depending on the
subroutine used, a predefined number of bytes, stored in
RAM2
) on the selected channel at the selected
data rate.
The EM9209 will wait for any packet on the selected channel at the selected data rate. When a packet is
received, the EM9209 examines the packet size header, and stores the corresponding number of bytes in
the
RXFIFO
(or, depending on the subroutine used, a predefined number of bytes, stored in
RAM2
) and sets
the IRQ signal Pin high.
The EM9209
RXFIFO
and
RXFIFO_Size
can be read through SPI.
The IRQ bit can be reset through the SPI
Clear_IRQ
command.
5.2.1.2
In Auto-calibration mode:
The center frequency of the VCO is tuned for a chosen channel frequency.
The result of the auto-calibration is directly written in the VCO center frequency register
VCO_Code[3:0]
.
5.2.1.3
In Standby mode:
The EM9209 control registers (
RAM2
) can be read or written.
5.2.1.4
In RAM2 initialization mode
The EM9209 configures it’s
RAM2
to default value and sets IRQ pin high when this action is finished.
5.3
Power management
The power management system of the EM9209 provides the necessary supplies, voltage and current
references for reliable operation in all modes. It includes low drop-out voltage regulators (LDO) for the RF
transceiver.
5.3.1 RF transceiver supply
There are 2 on-chip regulators, for the transceiver and the synthesizer’s analog part, which supply all
analog circuits in the RF transceiver. The voltage reference for these regulators is derived from a low noise
bandgap circuit. The regulators are enabled individually when needed.
5.3.2 Digital supply
A low power regulator generates the supply for all digital parts in the system (base-band, frequency
synthesizer logic and demodulator).
5.3.3 Bias generator
The EM9209 features a bias generator that utilizes a temperature compensated on-chip bandgap reference
and a calibrated, temperature dependent, PTAT reference current.
