The N PHYs contain up to four RF chains/PHY cores, however, only two are implemented.

Updating the chain selection

The chain selection is done via the PHY registers 0x0a1/0x0a2. To change the selected chains, set the lower 8 bits of 0x0a2 to 0x11, 0x22 or 0x33, if only one core is selected then the bit 0x1 in 0x0a1 needs to be set, otherwise cleared.

N PHY Update TXRX Chain

1. Initialize override to 0
2. Intiialize chain to 0x33

3. If nphy_txrx_chain is 0

   1. Set chain to 0x11
   2. Set override to 1

4. Else if nphy_txrx_chain is 1

   1. Set chain to 0x22
   2. Set override to 1
5. Maskset PHY Register 0xA2 with mask 0xFF00 and set with chain
6. If override
   1. Set bit 0x1 in PHY Register 0xA1
7. Otherwise
   1. Clear bit 0x1 in PHY Register 0xA1