Subversion Repositories funbase_ip_library

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-- HIBI has a genric called

--    fifo_sel_g

-- which affects which fifo and synchroniaztion are implemented

--

-- Ari Kulmala (a long long time ago :)

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mostly  changes things in double_fifo... vhds

Clock goes in the following way:

-- 0 synch multiclk

* uses multiclk_fifo

*ps (synch) clocks not used

-- 1 basic GALS 2FF synchronizer

pulsed clocks used in the synchronizer interface.

pulsed clock should be integer multiples of the actual clock,

period 50/50

(1 is ok, i.e. using the same clock for pulsed and regular)

HIBI is always in the synchronous side of the FIFO, IP writes through

asnchronous links

pulsed clocks should always be assigned!

-- 2 Gray FIFO (depth=2^n!),

pulsed clocks not used

uses cdc_fifo

-- 3 mixed clock pausible

pulsed clocks have to be clock that implement a pulse that is around

the rising edge corner of the corresponding regular clock.

i.e. (use courier font)

bus_clk          _______|^^^^^^^^^^|________|^^^^^^^^^^|

bus_pulsed    ________|^^^|_______________|^^^|______