I have the intention to use BCM20732S for my new project. As my PCB size is rather small, i have some limitation on the spcae for BCM20732S.
On the layout, please refer to page 23 of module datasheet.
1) In the first picture above, the L-shape GND is on the top layer? Meaning to say we can actually route traces and place components inside? Or it simply means the whole L-shape GND on top layer must be cleared?
2) 2nd picture, this should be a 2nd layer GND (internal). Meaning to say it has to be in one whole big piece without any breaksge? Or can I follow the shape from the 1st picture above?
In simple context, for the L-shaped GND, if it is meant for Antenna use, can I lay components and route traces on top of the L-shaped GND, but i will make sure there is no breakage of the GND along the way if this L-Shaped GND is on the top layer?
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1) (pg22) Yes, the ground is on top layer. The ground is actually a "L-shape" with a width of at least 3mm. And you cannot place any components within this "3mm" boundary.
2) (pg23) The ground is on second layer. This is a more practical approach as you can still place your components on L1 and maintain the L-shape ground on L2.
Yes, the L-shape ground is to achieve antenna efficiency. And as I said, the approach in (2) is a better one.
Btw, is there an opportunity for you to move to 20736S? The current SDK (ver 2.2.1) is not backward compatible with 20732.
Not of an issue. Its more for understanding how to use this part with best layout. So can i say if I use the GND on the inner layer, i can lay components right up to the edge of the BCM20732/6/7S chipset on the top layer?
Hi Boon T
One quick question, from the layout provided, can i safely say this module do not even require any tuning on the Antenna path?
It is simply a plug and play if i follow your layout?
The SIP module will not require any tuning on its antenna path. However I strongly advised you to adhere to the L-shape ground so that the antenna efficiency is maintained.
DO you have a reference design for BCM20737S?
I have some question on the Wiced sense reference design using BCM20737S thuogh.
Eg for pin 25, it is described as a pin tied to WP pin of embedded EEPROM. Will require a external pull high resistor. But in the reference design, pin25 is links to RTS_SCI (UART) of CP2105?
And pin 26 TMC, in datasheet it says remains unconnected if not in used. This pin is connected to GND though INTERNAL 10K ressitor. But in the reference design, even thuogh this pin is not used, it is not unconnected. In fact it is connected to GND through an EXTERNAL 10K resistor.
Any advise which to follow?
The reference design for the BCM20737S is the iBeacon Module design:
1. The UART of the CP2105 is connected to P3.
2. Connect GND through EXTERNAL 10K resistor.
Thanks for your reference schematics.
Question, can i understand more on the use of P0 and P15 in the schematics?
P0 i can understand it is just a normal GPIO for the power on/off.
What about P15?
What is the use for this? Do i need to include this in my design?
And for debugging, for BCM20737S, is the debugging using UART only? Or do i even need to debug?
One more question,how is programming done in this module? Through UART?
If it is, my communications to my CPU on board is through UART, any protection circuit to be used here?
Can i refer you to "WICED Smart HW Interfaces" doc within the SDK for more details on the GPIOs?
Yes through uart. But I am not aware that there is a need to deploy protection circuit. So is your module going to connect to a host?
Yes, my module will be connected to a HOST.
Is there any documents on programming guide? Eg, during programming, the module must be in reset state etc? Meaning hold reset pin low until programming done?
I read form the WICED HW interface document, there are 2 UART. One is HCI UART which inside describes it is used for programming and factory testing. And this HCI UART is not meant for application use.
My next question, if i use BCM20737S in my project, I need not do any programming? Everything is supplied from BCM when i purchased the module?
Sorry for asking so many questions in different emails.
All my train of thoughts are coming as I am doing up my schematics. So sorry about it.
One more question, do you have the Antenna performance simulation for BCM20737S? I need to know how should i orientate my module in order to get the best performance from it.
Is the Antenna report available for viewing?
I am interested to see the radiation pattern on different orientation for BCM20737S
You program the device through the HCI UART (it's dedicated to this function). In fact, that is the only type of programming supported.
You can program the device using either the SDK, or the command line tools described here: Programming the TAG2/TAG3 Board using command line tools