SX1232
High Link Budget Integrated UHF Transceiver
WIRELESS & SENSING
ERRATA NOTE
Errata Note
SX1232 - 868 & 915MHz
High Link Budget Integrated UHF Transceiver
Revision 3 - July 2013
© Semtech Corporation
1
SX1232
High Link Budget Integrated UHF Transceiver
WIRELESS & SENSING
ERRATA NOTE
Table of Contents
1
2
2.1
2.2
2.3
3
3.1
3.2
4
4.1
4.2
5
Chip Identification ......................................................................................................................................... 3
I and Q Calibration ........................................................................................................................................ 3
Description ...................................................................................................................................................... 3
Workaround ..................................................................................................................................................... 3
SW Implementation ......................................................................................................................................... 4
PayloadReady
Set for 31.25ns if FIFO is Empty ........................................................................................ 4
Description ...................................................................................................................................................... 4
Workaround ..................................................................................................................................................... 4
Erroneous IBM Data Whitening/De-Whitening ........................................................................................... 4
Description ...................................................................................................................................................... 4
Workaround ..................................................................................................................................................... 4
Revision History ............................................................................................................................................ 5
Table of Figures
Figure 1. Chip Marking ................................................................................................................................................... 3
Figure 2. SW Implementation ......................................................................................................................................... 4
Revision 3 - July 2013
© Semtech Corporation
2
SX1232
High Link Budget Integrated UHF Transceiver
WIRELESS & SENSING
ERRATA NOTE
1 Chip Identification
The V2B chips are identified as follows:
1) The
RegVersion
at address 0x42 returns 0x22.
2) The top marking described in Figure 1:
SX1232
yyww
xxxxxx
.xx-22
Figure 1. Chip Marking
2 I and Q Calibration
2.1 Description
By default in the SX1232, I&Q calibration is done at power-up and after a manual reset. In the V2B chip version, the
I&Q calibration is not optimal, and the user should manually perform it after a power-on reset or manual reset event,
to improve RSSI accuracy and Image Rejection.
2.2 Workaround
This following workaround procedure should be performed once after the power-on of the chip, after Reset if the
chip is Reset, and on any user-triggered calibration, initiated with bit
ImageCalStart,
in
RegImageCal.
1)
2)
3)
4)
5)
Go or stay in Standby mode.
Use 256 samples for RSSI averaging. To do so, set
RssiSmoothing
to ‘111’ in
RegRssiConfig.
Set
ImageCalStart
to ‘1’ to trigger a manual I&Q calibration.
Wait for 8 ms.
Set
RssiSmoothing
back to the desired value (‘010’ by default).
The use of the automatic calibration trigger, based on a pre-defined temperature change threshold, is therefore not
recommended. The user can still detect a large temperature variation with the flag
TempChange,
but one should
avoid using
AutoImageCalOn
= 1.
Revision 3 - July 2013
© Semtech Corporation
3
SX1232
High Link Budget Integrated UHF Transceiver
WIRELESS & SENSING
ERRATA NOTE
2.3 SW Implementation
This following pseudo code shows the SW implementation of this workaround:
// Rx I&Q re-calibration workaround
RadioWrite( 0x0E, 0x07 );
RadioWrite( 0x3B, 0x43 );
// Wait for 8ms
Sleep( 8 );
// Set RSSI default averaging back to 8 samples
RadioWrite( 0x0E, 0x02 );
Figure 2. SW Implementation
3
PayloadReady
Set for 31.25ns if FIFO is Empty
3.1 Description
When receiving in Packet mode with the SX1232, the microcontroller can be instructed to service the FIFO and read
the bytes it contains before the
PayloadReady
flag is set, thanks to the
FifoLevel
gauge. On the SX1232 V2B, the
duration of
PayloadReady
is very short (31.25ns) if the FIFO is already emptied at packet end, when this interrupt
fires.
This situation can happen if
FifoThreshold
and the corresponding
FifoLevel
interrupts are used to monitor the FIFO
content and offload it on-the-go,
FifoThreshold
being equal to the number of bytes stored in the FIFO.
3.2 Workaround
When
FifoLevel
interrupt is used to offload the FIFO, the microcontroller should monitor both PayloadReady and
FifoLevel
interrupts, and read only (FifoThrehold-1) bytes off the FIFO when
FifoLevel
fires.
4 Erroneous IBM Data Whitening/De-Whitening
4.1 Description
On the SX1232, the implementation of the IBM-compatible whitening/de-whitening algorithm is erroneous, which
makes it incompatible with the standard implementation.
Conditions:
CrcWhiteningType
= 1
DcFree
= 10
4.2 Workaround
The workaround is to use “unlimited Length Packet Format”, and process whitening/de-whitening in the host
microcontroller. Semtech is providing software implementations of this algorithm. Please contact your Semtech
representative for assistance.
Revision 3 - July 2013
© Semtech Corporation
4
SX1232
High Link Budget Integrated UHF Transceiver
WIRELESS & SENSING
ERRATA NOTE
5 Revision History
Revision
1
2
Date
May 2012
August 2012
Description/Changes
Initial release
Detail IQ calibration conditions
Add erratum on
PayloadReady
interrupt
Add erratum on CRC calculation with whitening On and CRC IBM
Correction on IBM whitening description
3
July 2013
Revision 3 - July 2013
© Semtech Corporation
5
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