CY7C68033 CYPRESS [Cypress Semiconductor], CY7C68033 Datasheet - Page 29
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CY7C68033
Manufacturer Part Number
CY7C68033
Description
Manufacturer
CYPRESS [Cypress Semiconductor]
Datasheet
1.CY7C68033.pdf
(33 pages)
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Document #: 001-04247 Rev. *D
Figure 17 diagrams the timing relationship of the SLAVE FIFO
signals during an asynchronous FIFO read. It shows a single
read followed by a burst read.
Sequence Diagram of a Single and Burst Asynchronous Write
Figure 19 diagrams the timing relationship of the SLAVE FIFO
write in an asynchronous mode. The diagram shows a single
write followed by a burst write of 3 bytes and committing the
4-byte-short packet using PKTEND.
FIFOADR
PKTEND
• At t = 0 the FIFO address is stable and the SLCS signal is
• At t = 1, SLOE is asserted. This results in the data bus being
• At t = 2, SLRD is asserted. The SLRD must meet the
• At t = 0 the FIFO address is applied, insuring that it meets
• At t = 1 SLWR is asserted. SLWR must meet the minimum
• At t = 2, data must be present on the bus t
• At t = 3, deasserting SLWR will cause the data to be written
FLAGS
asserted.
driven. The data that is driven on to the bus is previous data,
it data that was in the FIFO from a prior read cycle.
minimum active pulse of t
pulse width of t
in asserted with SLRD or before SLRD is asserted (that is
the SLCS and SLRD signals must both be asserted to start
a valid read condition).
the setup time of t
asserted (SLCS may be tied low in some applications).
active pulse of t
of t
SLWR or before SLWR is asserted.
deasserting edge of SLWR.
from the data bus to the FIFO and then increments the FIFO
SLWR
DATA
SLCS
WRpwh
. If the SLCS is used, it must be in asserted with
t=0
t
SFA
RDpwh
WRpwl
t =1
SFA
t
WRpwl
Figure 19. Slave FIFO Asynchronous Write Sequence and Timing Diagram
t=2
. If SLCS is used then, SLCS must be
t
SFD
. If SLCS is used, it must also be
and minimum de-active pulse width
t=3
N
t
t
FDH
WRpwh
RDpwl
t
FAH
t
XFLG
and minimum de-active
T=0
SFD
t
SFA
T=1
before the
t
WRpwl
T=2
t
SFD
T=3
t
N+1
FDH
t
WRpwh
T=4
The same sequence of events is also shown for a burst read
marked with T = 0 through 5. Note: In burst read mode, during
SLOE is assertion, the data bus is in a driven state and outputs
the previous data. Once SLRD is asserted, the data from the
FIFO is driven on the data bus (SLOE must also be asserted)
and then the FIFO pointer is incremented.
The same sequence of events are shown for a burst write and
is indicated by the timing marks of T = 0 through 5. Note: In
the burst write mode, once SLWR is deasserted, the data is
written to the FIFO and then the FIFO pointer is incremented
to the next byte in the FIFO. The FIFO pointer is post incre-
mented.
In Figure 19 once the four bytes are written to the FIFO and
SLWR is deasserted, the short 4-byte packet can be
committed to the host using the PKTEND. The external device
should be designed to not assert SLWR and the PKTEND
signal at the same time. It should be designed to assert the
PKTEND after SLWR is deasserted and met the minimum
de-asserted pulse width. The FIFOADDR lines are to be held
constant during the PKTEND assertion.
t
WRpwl
• The data that will be driven, after asserting SLRD, is the
T=5
updated data from the FIFO. This data is valid after a propa-
gation delay of t
Figure 17, data N is the first valid data read from the FIFO.
For data to appear on the data bus during the read cycle
(that is SLRD is asserted), SLOE MUST be in an asserted
state. SLRD and SLOE can also be tied together.
pointer. The FIFO flag is also updated after t
deasserting edge of SLWR.
t
SFD
T=6
t
N+2
FDH
t
WRpwh
T=7
t
WRpwl
T=8
XFD
t
SFD
CY7C68033/CY7C68034
T=9
t
t
from the activating edge of SLRD. In
N+3
WRpwh
FDH
[13]
t
PEpwl
t
XFLG
t
PEpwh
t
Page 29 of 33
FAH
XFLG
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