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
- Initialize override to 0
- Intiialize chain to 0x33
If nphy_txrx_chain is 0
- Set chain to 0x11
- Set override to 1
Else if nphy_txrx_chain is 1
- Set chain to 0x22
- Set override to 1
- Maskset PHY Register 0xA2 with mask 0xFF00 and set with chain
- If override
- Set bit 0x1 in PHY Register 0xA1
- Otherwise
- Clear bit 0x1 in PHY Register 0xA1