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Making PCB with highly integrated RF transceiver
AndJuan , 01-22-2017, 03:16 AM
I have some doubts before making a pcb with the electronic board with the RFM69 is an RF transceiver with SPI bus.
1- If I can put the RFM69 board on the same layer where the microcontroller will go.
2- If the SPI bus lines have to go as close as possible to the microcontoller and if as Fedevel said in "TIP # 016" put a resistor
​ in series on the legs SCK and MOSI (TX), MISO (RX) for a Possible crosstalk.
In the datasheet pag-70 "7.3. Reference Design" there is a schematic and do not put resistors in series in those lines and do not put anything into consideration in the design of the PCB.
3 - And if it is better, once located the SMF69 board in the pcb surround it with a generous polygon.
THX.
​ Here DataSheet
1- If I can put the RFM69 board on the same layer where the microcontroller will go.
2- If the SPI bus lines have to go as close as possible to the microcontoller and if as Fedevel said in "TIP # 016" put a resistor
​ in series on the legs SCK and MOSI (TX), MISO (RX) for a Possible crosstalk.
In the datasheet pag-70 "7.3. Reference Design" there is a schematic and do not put resistors in series in those lines and do not put anything into consideration in the design of the PCB.
3 - And if it is better, once located the SMF69 board in the pcb surround it with a generous polygon.
THX.
​ Here DataSheet
robertferanec , 01-23-2017, 10:59 AM
If you use the module, you should be fine with placing it almost anywhere on your board (I would place it somewhere on the edge or into corner).
What may not be a good sing is, that I could not find Recomended layout for the chip and the module soldering looks really bad ... I mean, really bad. So, who knows who actually designed the module and what rules they followed. However, if you have already tested the module and you are happy with it, it may be then ok.
PS: I am not sure about your schematic, but if you are using SPI and you are sending CLK from your microcontroller, I would use series termination resistor. Also, I do not think surrounding the module with GND is going to make some change.
What may not be a good sing is, that I could not find Recomended layout for the chip and the module soldering looks really bad ... I mean, really bad. So, who knows who actually designed the module and what rules they followed. However, if you have already tested the module and you are happy with it, it may be then ok.
PS: I am not sure about your schematic, but if you are using SPI and you are sending CLK from your microcontroller, I would use series termination resistor. Also, I do not think surrounding the module with GND is going to make some change.
AndJuan , 01-24-2017, 02:39 AM
Hello,
I totally agree on the solderings really bad and the layout design.
Unfortunately I do not have the module RFM69 but they are on the way and I have not tried them either.
But because of its characteristics for me are ideal.
Thank you.
I totally agree on the solderings really bad and the layout design.
Unfortunately I do not have the module RFM69 but they are on the way and I have not tried them either.
But because of its characteristics for me are ideal.
Thank you.
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