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#1 2015-Feb-20 10:48:25

syed.haq
Member
Registered: 2015-Jan-20
Posts: 5

DIFS values

Hi,
I am trying to experiment with different values of DIFS by altering this section of the code in mac low header
#define T_DIFS (T_SIFS + 2*T_SLOT)
However, this does not seem to have any effect on the DIFS value. I tried to locate if there was any alternate place where this was being changed but could not find it. These values are being stored in a register but doesn't look like they're being used.

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#2 2015-Feb-20 11:09:01

chunter
Administrator
From: Mango Communications
Registered: 2006-Aug-24
Posts: 1212

Re: DIFS values

The code in CPU_LOW sets the value in that register. The value is used by the wlan_mac_dcf_hw core that runs in the FPGA fabric. That core is responsible for some of the MAC state that requires deterministic timing. For example, that core knows to exert an "idle for DIFS" signal to the backoff subsystem a DIFS period after the medium state goes idle. You can change that value in code and the hardware will reflect that change.

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