RTX-24EM-HP
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. A
Tel.: +390546941124 – Fax: +390546941660 Page 12
http://www.aurel.it
7.2
Standby Mode
When ENABLE (Pin 10) or nRESET (Pin 4) is high the RTX-24EM-HP wakes up in standby mode at about t
PD-
STBY
seconds (see Table 6). The SPI register memory is then set to 0 and the SPI waits for the host
programming. In standby mode all internal circuits are disabled and can be accessed, including the crystal
oscillator. The host microcontroller can program the RTX-24EM-HP for any operational mode.
7.3
RAM2 Init
The RTX-24EM-HP can be configured using a 16 registers memory RAM2. RAM2 is resetted to 0 when
ENABLE (Pin 10) or nRESET (Pin 4) is set from GND to Vcc. In order to avoid 16 different SPI write cycles, a
dedicated subroutine located at
ROM_BOOT_Address = 0
will initialize most RAM2 addresses to their
default values. This procedure takes about t
RAM2_INIT
seconds (see Table 6).
7.4
Auto-cal
VCO center frequency
The RTX-24EM-HP frequency synthesizer has an Auto-calibration mode that must be run periodically by the
host microcontroller. This keeps the channel frequency and FSK modulator operating within specification.
Analog components in this block are sensitive to temperature variation, therefore performance may
degrade or the link may fail if not run periodically. Typically, Auto-calibration should be run when changing
channels or if the operating temperature changes by more than 10 to 20 °C. This procedure takes about
t
VCO_CAL
seconds (see Table 6).
PTAT reference current
The internally generated PTAT current can be self calibrated using an internal PTAT generator.
This
procedure takes about t
PTAT_CAL
seconds (see Table 6).
7.5
Transmit
In Transmit mode, the RTX-24EM-HP outputs a FSK-modulated packet, it returns to receive mode or
standby mode with the crystal oscillator enabled and sets the interrupt pin IRQ high. Depending on the
choosen subroutine the RTX-24EM-HP can transmit the whole TXFIFO (till TXFIFO size = 0) or a predefined
number of bytes programmed in RAM2.
Transmit mode is activated from Receive mode or from Standby mode (with crystal oscillator enabled)
using the SPI command
Send_TXFIFO
.
7.6
Receive
The RTX-24EM-HP in receive mode waits for a FSK-modulated packet. After receiving a suitable packet it
sets the IRQ pin high. Depending on the choosen subroutine, it can either read the size of the packet to be
received in the header or in RAM2.
