CY7C1470V33
CY7C1472V33
CY7C1474V33
Document #: 38-05289 Rev. *I Page 13 of 29
possible to capture all other signals and simply ignore the
value of the CLK captured in the boundary scan register.
Once 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 since the PRELOAD part of the command is not
implemented, putting the TAP to the Update-DR state while
performing a SAMPLE/PRELOAD instruction will have 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 tTL
Test Clock
(TCK)
123456
T
est Mode Select
(TMS)
tTH
Test Data-Out
(TDO)
tCYC
Test Data-In
(TDI)
tTMSH
tTMSS
tTDIH
tTDIS
tTDOX
tTDOV
DON’T CARE UNDEFINED
TAP AC Switching Characteristics Over the Operating Range[9, 10]
Parameter Description Min. Max Unit
Clock
tTCYC TCK Clock Cycle Time 50 ns
tTF TCK Clock Frequency 20 MHz
tTH TCK Clock HIGH time 20 ns
tTL TCK Clock LOW time 20 ns
Output Times
tTDOV TCK Clock LOW to TDO Valid 10 ns
tTDOX TCK Clock LOW to TDO Invalid 0 ns
Set-up Times
tTMSS TMS Set-up to TCK Clock Rise 5 ns
tTDIS TDI Set-up to TCK Clock Rise 5 ns
tCS Capture Set-up to TCK Rise 5 ns
Hold Times
tTMSH TMS Hold after TCK Clock Rise 5 ns
tTDIH TDI Hold after Clock Rise 5 ns
tCH Capture Hold after Clock Rise 5 ns
Notes:
9. tCS and tCH refer to the set-up 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. tR/tF = 1 ns.
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