Member | Action | Date |
---|---|---|
![]() |
Updated
[Deprecated] How do I use the CTUNE token for EFR32? on Zigbee and Thread Wireless Knowledge Base
Note: This KBA has been marked as deprecated. More updated KBAs on this topic can be found here:HFXO Capacitor Bank (CTune) calibration on EFR32 Saving CTUNE value as manufacturing token
QuestionHow do I use the CTUNE token for EFR32? AnswerThe EFR32 38.4MHz crystal does not require external loading caps, as there is a tunable capacitor bank in the EFR32 that can be used instead. Different tune values can be written to registers to observe the corresponding frequency offset, and the CTUNE token is used to store the value for use by the application. Here in this example, we refer to nodetest commands.
Once your EFR32 device is programmed with nodetest, if you enter “tokdump” you should see the ctune token amongst the tokens reported: [C354] MFG_CTUNE FF FF
Note that there are also nodetest commands "setCtune" and "getCtune" where you can set and read the CTUNE register values. This is helpful if you want to try multiple specific ctune values and measure their affect prior to writing the token. From the nodetest "help" output: setCtune u4 - set CTUNE registers (CMU->HFXOSTEADYSTATECTRL_CTUNE and CMU->HFXOSTARTUPCTRL_CTUNE) getCtune - get CTUNE register value
A default / erased value for MFG_CTUNE corresponds to using the nodetest default ctune register value of 0x142. The EFR32 reference manual provides a formula for ctune: Sets oscillator tuning capacitance. Capacitance on HFXTAL_N and HFXTAL_P (pF) = Ctune = Cpar + CTUNE<8:0> x 40fF. Max Ctune 25pF (CLmax ~12.5pF) CL(DNLmax)=50fF ~ 0.6ppm (12.5ppm/pF)
With this calculation, the default of 0x142 (322 decimal) and no loading caps installed (as is the case with the BRD4151A modules in the WSTK) corresponds to a capacitance of 12.8pF.
You can issue the nodetest command "tokWrite c354" to write this token: tokWrite u2 - Write all data of a token (u2=creator code)
Similar set/get of CTUNE register values can be achieved with RAIL test as well. See the RAIL test user documentation for additional details.
Setting CTUNE token can also be achieved via Simplicity Commander. See the Simplicity Commander User Guide UG162 for additional details on setting tokens. |
Nov 24 2020, 9:55 PM |
![]() |
Replied
to
BGM13P32 Voltage Requirements
Thomas - are you still having this issue? If so, what SDK version are you using to test this? And how are you monitoring the tx current? Note that the BGM13P32 +19dBm version is configured with the PA connected to the main supply and not the DCDC, while the BGM13P22 +8dBm version is configured with the PA connected to the DCDC. Can you confirm whether you are using BGM13P32 or BGM13P22? |
Dec 11 2019, 2:14 AM |
![]() |
Replied
to
BLE112 slow clock on power on? Do they have to be reflowed??
Johan - I have followed up internally and we are not aware of any BLE112 module production issues. You should not need to reflow the module to allow it to work properly. Your observations of needing to heat the modules suggests that the initial solder reflow for assembling these modules onto your boards may not have been sufficient for proper reflow. Hand-soldering modules to PCBs is not a very controlled and repeatable process so it seems possible that there was a difference between your 2015 project assembly and this project. Do you have boards which are still not functional which you can x-ray to observe the module solder connections to your board?
Show more
|
Oct 08 2019, 1:58 PM |
![]() |
Selected an answer for
Our customer like to use a new BGM13P module in explosive risk environments?
ATEX declaration for BGM13P22A is attached for reference.
Show more
|
Aug 06 2019, 7:27 PM |
![]() |
Replied
to
Our customer like to use a new BGM13P module in explosive risk environments?
ATEX declaration for BGM13P22A is attached for reference.
Show more
|
Aug 06 2019, 7:27 PM |
![]() |
Selected an answer for
Soldermask size around BGM121 pads
Hi Rohan, Please see this KBA for the answer to this and other assembly questions you may have. Best regards, -Bill |
Jul 03 2019, 1:30 PM |
![]() |
Selected an answer for
Conductive/non-conductive filling via-in-pads
Hello Rohan, Best solution is to fill and plate. The via in pad needs to not result in any depression, hole or 'well' structure in the pad as this may result in re-flow solder defects.
Best,
|
Jul 03 2019, 1:29 PM |
![]() |
Selected an answer for
Question on BRD4302a manufacturing notes.
Hello Rohan,
High end CAD tools provide methods to specify the via make-up, including fill. In this way the specification of the vias is provided as part of the design files given to the PCB fabricator and no further action is necessary. Consult with your CAD tool vendor to find out if they have this capability and for instructions. Alternately you can always add fabrication notes to the PCB fabrication print provided to the PCB fabricator as part of the design file. This is the print which specifies the PCB dimension, drill holes, layer stack and any special instructions for the fabrication and for which is typically used by the PCB fabricator in providing job quotes. Check with your PCB fabricator to also see if they have a preference for specifying special vias.
Best regards,
-Bill |
Jul 03 2019, 1:28 PM |
![]() |
Updated
KBA_BT_1304: Antenna tuning for BGM12x (coin-cell usage example) on Knowledge Base
Introduction
This article shows how tune the antenna integrated into the BGM12x with the specific use case of placing a coin-cell battery behind the SiP, therefore enabling extremely compact designs.
To better follow this article it is recommended to watch our BGM12x related videos, BGM121/123 Hardware Design Guidelines and BGM121/123 Antenna Robustness.
Effects of placing coin-cell battery in tuned design
To understand the effects of the coin-cell battery on the antenna matching we took a BGM121 test board and placed a coin-cell in the back with a piece of blu-tak to keep it in place.
Figure 1 - BGM121 test board with coin-cell battery attached
The antenna matching can be seen in the following figures, first for the test board without battery and then after attaching the coin-cell battery.
Figure 2 - Original antenna matching for the BGM121 test board
Figure 3 - Antenna matching for BGM121 test board after attaching the coin-cell battery
Markers 1, 2 and 3 correspond to the beginning, middle, and end of the Bluetooth band. As it is visible in Figure 3 the presence of a metallic body (coin-cell) shifts the antenna tuning outside of the Bluetooth band. This is mostly due to the fact that the coin-cell is covering part of the copper clearance area and therefore reducing the antenna current loop.
Re-tuning the antenna
To counteract this frequency shift we can extend the clearance area simply by scrapping away the ground layer as shown in Figure 4. Due to the the underlying uncertainty on how much it needs to be extended we’ll just extend it about 50% more as it is then easier to re-add a metal plane in order to fine-tune the clearance area.
Figure 4 - Extending the copper clearance area
The antenna matching of the modified board is show in the next figure.
Figure 5 - Antenna matching after extending the copper clearance area
The matching is still off-band but this time it is towards the lower frequencies which can be compensated by reducing the copper clearance. To reduce the copper clearance we simply cover it with a piece of metal (a shield from one of our modules in this specific case) until we get the correct matching as shown in the next figure.
Figure 6 - Reducing the copper clearance area to fine tune antenna matching
The antenna matching is now back into the Bluetooth band and very close to the original design.
Figure 7 - Antenna matching after reducing size of the copper clearance area
Conclusion
The presence of metal very near to the BGM12x can have a negative impact on the antenna matching. However, it is easy to compensate the effect by adjusting the size of the copper clearance area to bring the antenna matching back into the Bluetooth band and ensure the best RF performance for your design. |
Apr 03 2019, 1:23 PM |
![]() |
Updated
BGM12x SiP Module Layout Recommendations on Knowledge Base
The BGM121/BGM123 Blue Gecko Bluetooth® SiP Module family is targeted for applications where ultra-small size, reliable high RF performance, low-power consumption and easy application development are key requirements. At 6.5 x 6.5 x 1.4 mm the BGM121/BGM123 module fits applications where size is a constraint. BGM121/BGM123 also integrates a high performance, ultra robust antenna, which requires minimal PCB, plastic and metal clearance. The total PCB area required by BGM121/BGM123 is only 51 mm2. The BGM12x SiP module has an internal chip antenna which is properly tuned with a GND loop, i.e. copper clearance area, on the carrier board. For the best possible antenna performance Silicon Labs recommends to precisely follow the layout suggestions around the SiP module including the copper clearance area, as shown in the following figures.
In order to have the internal antenna tuned the GND pins 53 and 54 of BGM12x shouldn’t directly be tied together. They need to be connected to each other through the GND loop which is routed along the circumference of the copper clearance area. This GND loop makes the antenna resonate and its size determines the resonant frequency, so its layout parameters should exactly be followed as shown in the figure above. The SiP module should be placed at the board edge of the carrier PCB.
If these layout recommendations above are precisely followed on the carrier board of the SiP module then the BGM12x has the following unique features:
The impedance of the BGM12x SiP module’s built-in antenna can be fine-tuned by adjusting the copper clearance area (i.e. GND loop) on the carrier board. The figure below shows the return loss (S11) – where the resonant frequency can also be observed from the notches – of the built-in antenna with different copper clearance width. This tuning method is a unique feature for BGM12x, so the module antenna can get tuned on any custom design layout and thus exceptional RF performance can always be achieved with this SiP module. The generally recommended copper clearance area dimensions are 5.0 x 2.2 mm on the top layer - when there isn't any metal object in the close proximity of the antenna and copper clearance area. If any metal object, e.g. coin cell battery, is mounted or attached onto the carrier board beneath the antenna area of the SiP module on the opposite layer, then the suggested GND loop dimensions are 6.2 x 2.2 mm - this assumes that the front edge of the coin cell battery is in line with the front edge of the PCB.
A more detailed guidance on the antenna tuning of the BGM12x SiP module can also be seen under the below KB article here: http://community.silabs.com/t5/tkb/articleprintpage/tkb-id/BluetoothandWiFi@tkb/article-id/563 https://www.silabs.com/community/wireless/bluetooth/knowledge-base.entry.html/2017/01/10/antenna_tuning_forb-R5av
The optimal board design mentioned above in point 4 refers to the generally recommended GND plane size of monopole-type antennas. Since the GND plane itself is also the part of the monopole-type antennas it is important to ensure big enough GND reference for the antenna. The smaller GND reference is ensured for any monopole-type antenna the weaker antenna performance can be expected. If the GND plane size goes below quater-wavelength then the antenna performance drops quickly.
To have the best antenna performance with BGM12x Silicon Labs recommends to use 40...50 mm wide carrier board. If the module antenna is kept tuned by following the layout recommendations, especially around the copper clearance area and GND loop, then the following curve describes the effects of the GND plane on the antenna efficiency.
RF performance when using BGM12x SiP module on a very small carrier board: The minimum recommended board design width is 10 mm. The antenna efficiency in that case is around -12 dB. Under these conditions, the tested practical RF range with the BGM12x SiP module in office environment is about 15 meters.
The following figure shows the antenna efficiency versus board size curves for different antennas. As the curves show below the considerable antenna efficiency degradation is a general feature of any monopole-type antenna.
Training & demonstration videos: BGM121/123 Hardware Design Guidelines: https://www.youtube.com/watch?v=5DCn7AzIyig BGM121/123 Antenna Robustness: https://www.youtube.com/watch?v=LA2j4AXqd7Q
|
Mar 30 2019, 1:47 AM |