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#1 2018-Jun-08 03:30:53

vutran
Member
Registered: 2017-Jul-01
Posts: 35

802.11 4 Radios cannot turn on RF_C/D

Hi,

I've modified the reference 802.11 to use 4 antennas as described in this App note. The project can compile smoothly. I've checked the software and it seems it supports RF_C, and RF_D, so I just update the .bit, .xml and .bmm file to generate a new .bin file. However, the function node.set_rx_ant_mode('RF_C') does not switch the reception interface to RF_C, the red LED is not turned on. The same thing with RF_D. And my phone cannot see "MANGO_AP". It's strange that the rx_phy core connects the 4 Rx_en to the same line, but RF_A/B work and RF_C/D doesn't.
Can you please help me solve this? Thanks.

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#2 2018-Jun-11 04:14:15

vutran
Member
Registered: 2017-Jul-01
Posts: 35

Re: 802.11 4 Radios cannot turn on RF_C/D

After changing some code:
(1) iic_init_eeprom is not found in w3_low.c, and become implicit declaration
(2) BSP does not recognize the new FMC iic eeprom module automatically
(3) include RF_C, RF_D for TX in util.py
I can change the interface to any one of RF_A/B/C but not RF_D. The LED TX/TX at RF_D is blinking but my phone cannot see the MANGO_AP. Can you say what is the problem with RF_D?

Last edited by vutran (2018-Jun-11 04:15:00)

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#3 2018-Jun-12 09:34:50

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 4924

Re: 802.11 4 Radios cannot turn on RF_C/D

It's been a long time since I tried the 4-radio 802.11 extension; a few ideas:

-To save space the latest Rx PHY does not implement packet detection logic on the RFC/D inputs. If you want to operate Rx on RFC/D you will need to modify the Rx PHY core to duplicate the packet detect blocks from RFA/B to the RFC/D inputs.

-You must modify the C code to enable 4-radio support. At a minimum you must uncomment the WLAN_4RF_EN macro definition so the radio_controller and ad_controller can initialize all 4 interfaces

BSP does not recognize the new FMC iic eeprom module automatically

This is a problem - you must verify the BSP is configured with the correct driver for every pcore in the hardware design. Open the BSP settings and verify both instances of the EEPROM controller are associated with the w3_iic_eeprom_axi driver.

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#4 2018-Jun-12 12:23:29

vutran
Member
Registered: 2017-Jul-01
Posts: 35

Re: 802.11 4 Radios cannot turn on RF_C/D

I meant I managed to switch the Tx/Rx among all antennas already. But when using RF_D, my phone cannot detect the MANGO-AP though the LEDs are blinking. RF_A/B/C are ok. Is there any problem with the timing or placement of the components in the FPGA?

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#5 2018-Jun-14 15:06:10

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 4924

Re: 802.11 4 Radios cannot turn on RF_C/D

It could be an I/O timing issue, it's hard for me to debug remotely. You could test this theory by adjusting the I/Q alignment in the AD9963 ADC config (i.e. if the RF D ADC lines are delayed, it might be capturing misaligned I/Q). This would require modifying register settings in ad_init() (or in your own code after calling ad_init()).

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