Cypress FX2LP - Manual (Page 3)

February 19, 2008 Document No. 001-15342 Rev. ** 3
AN6077
Figure 2 shows the GPIF Designer view of the FIFO Read
waveform.
FIFOWR
When creating the FIFOWR waveform the following timing
parameters must be met.
tWR
pwl
- SLWR Pulse Width LOW = 50 ns (minimum)
tWR
pwh
- SLWR Pulse Width HIGH = 50 ns (minimum)
tSFD - SLWR to FIFO DATA Setup Time= 10 ns (mini-
mum)
tFDH - FIFO DATA to SLWR Hold Time = 10 ns (minimum)
tXFD - SLWR to FLAGS Output Propagation Delay =
70 ns (maximum)
This results in the following sequence:
Figure 3 shows the GPIF Designer view of the FIFO Write
waveform. Figure 4 and Figure 5 show the view of the GPIF
waveforms in the gpif.c file. This is the same as is seen in the
GPIF Tool utility.
Figure 2. FIFO Read Waveform in GPIF Designer
Figure 3. FIFO Write Waveform in GPIF Designer
s0 Sample the full flag of the peripheral. If the peripheral
is ‘not full’, proceed to s1, otherwise proceed to s6 to
trigger an interrupt and abort the GPIF waveform.
s1 Assert the SLWR strobe and drive the data bus and
wait for three cycles to meet the tWR
pwl
parameter.
s2 Deassert the SLWR and increment the FIFO pointer.
s3 Branch to IDLE.
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