CY7C1480V25
CY7C1482V25
CY7C1486V25
Document #: 38-05282 Rev. *H
Page 14 of 32
The SRAM clock input might not be captured correctly if there
is no way in a design to stop (or slow) the clock during a
SAMPLE/PRELOAD instruction. If this is an issue, it is still
possible to capture all other signals and simply ignore the
value of the CLK captured in the boundary scan register.
After the data is captured, it is possible to shift out the data by
putting the TAP into the Shift-DR state. This places the
boundary scan register between the TDI and TDO balls.
Note that because the PRELOAD part of the command is not
implemented, putting the TAP to the Update-DR state while
performing a SAMPLE/PRELOAD instruction has the same
effect as the Pause-DR command.
BYPASS
When the BYPASS instruction is loaded in the instruction
register and the TAP is placed in a Shift-DR state, the bypass
register is placed between the TDI and TDO balls. The
advantage of the BYPASS instruction is that it shortens the
boundary scan path when multiple devices are connected
together on a board.
Reserved
These instructions are not implemented but are reserved for
future use. Do not use these instructions.
TAP Timing
TAP AC Switching Characteristics
Over the Operating Range
[9, 10]
Parameter
Description
Min
Max
Unit
Clock
t
TCYC
TCK Clock Cycle Time
50
ns
t
TF
TCK Clock Frequency
20
MHz
t
TH
TCK Clock HIGH time
20
ns
t
TL
TCK Clock LOW time
20
ns
Output Times
t
TDOV
TCK Clock LOW to TDO Valid
10
ns
t
TDOX
TCK Clock LOW to TDO Invalid
0
ns
Setup Times
t
TMSS
TMS Setup to TCK Clock Rise
5
ns
t
TDIS
TDI Setup to TCK Clock Rise
5
ns
t
CS
Capture Setup to TCK Rise
5
ns
Hold Times
t
TMSH
TMS Hold after TCK Clock Rise
5
ns
t
TDIH
TDI Hold after Clock Rise
5
ns
t
CH
Capture Hold after Clock Rise
5
ns
Notes
9. t
CS
and t
CH
refer to the setup and hold time requirements of latching data from the boundary scan register.
10. Test conditions are specified using the load in TAP AC Test Conditions. t
R
/t
F
= 1 ns.
t
TL
Test Clock
(TCK)
1
2
3
4
5
6
Test Mode Select
(TMS)
tTH
Test Data-Out
(TDO)
tCYC
Test Data-In
(TDI)
tTMSH
tTMSS
tTDIH
tTDIS
tTDOX
tTDOV
DON’T CARE
UNDEFINED
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