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 19
http://www.aurel.it
9.
Programming interface
This section describes how to program the RTX-24EM by writing to the EM9209 RAM2 or by booting and
running in ROM stored subroutines.
9.1
RAM2, RAM1 reset
The EM9209 automatically performs a power on reset to RAM1 and RAM2 after ENABLE (Pin 10) or nRESET
(Pin 4) is set to Vcc from GND.
After reset, all RF communication parameters must be reconfigured and the PLL auto calibration cycle must
be initiated again.
9.2
RAM2 Initialization
The EM9209 has a dedicated subroutine located at the
ROM_Boot_Address
=
0
which will initialize the
RAM2
memory to its default state (see Section 12).
To perform the
RAM2
initialization:
•
ENABLE (Pin 10) or nRESET (Pin 4) must be set to Vcc.
•
Crystal oscillator must be started by writing 0b111000000100 (0xE04) in the
RAM2
at the address
0
.
•
Quartz activity can be monitored through
Status[1]
by using a simple
Stop_Micro
SPI command, for
example. When
Status[1]
has gone low, the
RAM2
initialization subroutine can be executed.
•
Use SPI command
Write_RAM1
with address =
13
and data_write =
1184 .
This will initialize RAM2 with
RB_Inst_Dis = 1 and this allows the user to manually select the subroutine to be stored in RAM1.
•
Use SPI command
ROM_Boot
with argument
ROM_Boot_Address
=
0.
•
Use then the SPI command
Start_Micro
.
•
The end of initialization will be signaled with IRQ going high. SPI command
Clear_IRQ
allows clearing
the interrupt.
9.3
Internal PTAT current auto calibration
This auto-calibration is used to calibrate the current delivered by the internal PTAT generator (Proportional
To Absolute Temperature).
The EM9209 has a dedicated subroutine located at the
ROM_Boot_Address
=
33
which will perform the
calibration.
To perform the auto calibration:
•
ENABLE (Pin 10) or nRESET (Pin 4) must be set to Vcc.
•
Crystal oscillator must be started (see section 9.2)
•
RB_Inst_Dis must be set to 1 (if RB_Inst_Dis has been previously set = 1, see section 9.2, this step can
be omitted).
•
Use SPI command
ROM_Boot
with argument
ROM_Boot_Address
=
33.
•
Use then the SPI command
Start_Micro
.
•
The end of auto calibration will be signaled with IRQ going high. SPI command
Clear_IRQ
allows
clearing the interrupt.
