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From: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Date: Tue, 12 Nov 2013 15:55:43 +0400
Message-ID: <CAHNKnsShTMiH-Bo+T0ydwFwpgoTd-Mx-BZXjP-1xoCE+w-vzkQ@mail.gmail.com>
Subject: Atheros AR5xxx DSSS-OFDM mode support
To: ath5k-devel@lists.ath5k.org, freebsd-wireless@freebsd.org
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Hi list,

we test pretty old hardware based on AR5414 chip with pretty old
madwifi driver, which even use binary hal. Our spectral analyzer shows
that in 2.4GHz band this chip transmits OFDM-preamble with any of the
OFDM rates (6-54 mbps), instead of .11b-compatable DSSS-preamble. Does
anybody could provide some clue: is this chip supports DSSS-OFDM mode
according to section 19.7 of IEEE 802.11-2012?

When I digging the ath5k code I faced the AR_PHY_MODE (0xa200)
register, which seems to controls the behavior of chip. This register
contains two interesting bit:
AR_PHY_MODE_MOD_CCK bit 0 (0x00000001)
AR_PHY_MODE_MOD_DYN bit 3 (0x00000004)

If I am correctly understand, _MOD_DYN just enables the CCK (DSSS)
block. But what the purpose of the AR_PHY_MODE_MOD_CCK bit?

-- 
BR,
Sergey