HOST INTERFACE
Data Device Corporation DS-BU-67301B-G
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HOST_CLK
nDATA_RDY
CPU_DATA
CPU_
WORD
_EN[1:0]
RD_nWR
MEM
_
nREG
ADDR
_
LAT
nDATA_
STRB
nSELECT
CPU
_nLAST
CPU_nSTOP
tSS
tRDD
tLS
tCLK
tDH
tRDD
tCS
tSH
tCH
tALS
tALH
Data Data Data
Data Data
Data Data Data
tAH
tAH
tDS
Address
tAS
tAH
tDH
tAS
tAS
tAS
tLH
tLS
tLH
tWait
tSHC
Data
tAH
Figure 44. Synchronous, Multiplexed Address - 32-bit Sequential Burst Write Transfer
Timing
Figure 44 Notes:
1. With nSELECT asserted low and valid address presented on CPU_DATA, a
positive pulse on the ADDR_LAT input satisfying t
ALS
and T
AHL
will result in the
Total-AceXtreme® latching the starting address for the sequential burst. One
host clock cycle later, a one-clock-cycle wide pulse of nDATA_STRB (low)
while nSELECT remains asserted (low) initiates the sequential burst transfer.
nSELECT must be asserted low through the remainder of the burst cycle. The
nDATA_RDY output is initially asserted low on the same host clock cycle
when the Total-AceXtreme latches the first data word from the data bus.
CPU_nLAST must be asserted high until the last word is to be written. On the
rising host clock edge following CPU_nLAST asserting low, the last word
latched from the data bus, and nDATA_RDY is de-asserted (high). At this time
(or later) nSELECT must be de-asserted high, completing the burst read
transfer.
2. The CPU_WORD_EN[1:0] inputs are used to specify which 16-bit data
memory word(s) are valid for this transfer. If either or both these bits is ‘0’,
then the corresponding 16-bit word(s) will not be written to Total-AceXtreme
memory. These inputs should be tied high if unused.
3. Unless the Total-AceXtreme command FIFO is full, CPU_nSTOP is not
asserted, and will remain high.
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