Communicating with Romeo2 and Tango3 Devices
14 Communicating with Romeo2 and Tango3 Devices
The major difference between Romeo2, Tango3, and Echo is the ID and header that is by Echo and
Romeo’s data managers. This can affect communication between the devices.
14.1 ID Length Mismatch
There is a mismatch between the ID lengths expected by the data managers in Romeo2 and Echo. Echo
has a variable length ID and header, whereas Romeo2 has a fixed 8 bit ID and 4 bit, fixed format, header,
either 0110 or 1001.
The header for Echo can be setup for 4 bits and set to 0110 or 1001 using the configuration options in the
Echo header file. The ID on Echo is limited to 2, 4, 5, or 6 bits in length and thus not directly compatible
with Romeo2’s data manager and the Tango3 device driver.
There are two cases which need to be considered: Echo is transmitting to Romeo2 and Echo is receiving
from Tango.3
14.1.1 Case (i) – Echo Transmitting
When Echo is transmitting, configure the driver to send 8 bits for the ID and thus allow Romeo2 to be
addressed. The driver has complete control of the exact bits sent and can send 8 bits at the ID stage.
Sending 8 bits can be achieved by setting ECHO_ID_LENGTH in Echo.h to 8: this sends all 8 bits of the ID in
the transmit buffer.
14.1.2 Case (ii) – Echo Receiving
The Tango3 driver transmits a fixed length 8 bits in the ID sequence. Echo can receive messages with 8 bit
ID fields. Any 6 bits from the 8 transmitted may be matched by the Echo data manager to the 6 bits in the
ID register. For this reason, choose IDs that are unique for all devices (if desired).
14.2 Compatible Set Up
To be compatible, several things must be configured correctly:
•
The headers must be same
— Echo must be set up for 4 bits: 0110
— Romeo must be set up for header detection (HE = 1)
— Tango must send using the header format (TangoSendPreamble_IDand TangoSendData)
The data rates must be the same, between 2 kbps and 10 kbps
The modulation type must be the same, either OOK or FSK
•
•
•
The transmission and reception frequencies must be the same: Echo must be set up to ensure
transmission and reception on exactly 315 MHz, 434 MHz, etc.
•
Echo must be set up with ECHO_ID_LENGTHas 8 bits
Software Drivers for MC33696, Rev. 1
Freescale Semiconductor
47
FREESCALE [ Freescale ]
