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參數資料
| 型號： | SN74BCT8240ANT |
| 廠商： | Texas Instruments, Inc. |
| 英文描述： | SCAN TEST DEVICES WITH OCTAL INVERTING BUFFERS |
| 中文描述： | 掃描測試設備與八進制反向緩沖器 |
| 文件頁數： | 14/26頁 |
| 文件大?。?/td> | 473K |
| 代理商： | SN74BCT8240ANT |
SN54BCT8240A, SN74BCT8240A
SCAN TEST DEVICES
WITH OCTAL INVERTING BUFFERS
SCBS067E – FEBRUARY 1990 – REVISED DECEMBER 1996
14
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
timing description
All test operations of the ’BCT8240A are synchronous to TCK. Data on the TDI, TMS, and normal-function inputs
is captured on the rising edge of TCK. Data appears on the TDO and normal-function output terminals on the
falling edge of TCK. The TAP controller is advanced through its states (as shown in Figure 1) by changing the
value of TMS on the falling edge of TCK and then applying a rising edge to TCK.
A simple timing example is shown in Figure 8. In this example, the TAP controller begins in the Test-Logic-Reset
state and is advanced through its states, as necessary, to perform one instruction-register scan and one
data-register scan. While in the Shift-IR and Shift-DR states, TDI is used to input serial data and TDO is used
to output serial data. The TAP controller is then returned to the Test-Logic-Reset state. Table 4 details the
operation of the test circuitry during each TCK cycle.
Table 4. Explanation of Timing Example
TCK
CYCLE(S)
TAP STATE
AFTER TCK
DESCRIPTION
1
Test-Logic-Reset
TMS is changed to a logic 0 value on the falling edge of TCK to begin advancing the TAP controller toward
the desired state.
2
Run-Test/Idle
3
Select-DR-Scan
4
Select-IR-Scan
5
Capture-IR
The IR captures the 8-bit binary value 10000001 on the rising edge of TCK as the TAP controller exits the
Capture-IR state.
6
Shift-IR
TDO becomes active and TDI is made valid on the falling edge of TCK. The first bit is shifted into the TAP
on the rising edge of TCK as the TAP controller advances to the next state.
7–13
Shift-IR
One bit is shifted into the IR on each TCK rising edge. With TDI held at a logic 1 value, the 8-bit binary value
11111111 is serially scanned into the IR. At the same time, the 8-bit binary value 10000001 is serially scanned
out of the IR via TDO. In TCK cycle 13, TMS is changed to a logic 1 value to end the IR scan on the next
TCK cycle. The last bit of the instruction is shifted as the TAP controller advances from Shift-IR to Exit1-IR.
14
Exit1-IR
TDO becomes inactive (goes to the high-impedance state) on the falling edge of TCK.
15
Update-IR
The IR is updated with the new instruction (BYPASS) on the falling edge of TCK.
16
Select-DR-Scan
17
Capture-DR
The bypass register captures a logic 0 value on the rising edge of TCK as the TAP controller exits the
Capture-DR state.
18
Shift-DR
TDO becomes active and TDI is made valid on the falling edge of TCK. The first bit is shifted into the TAP
on the rising edge of TCK as the TAP controller advances to the next state.
19–20
Shift-DR
The binary value 101 is shifted in via TDI, while the binary value 010 is shifted out via TDO.
21
Exit1-DR
TDO becomes inactive (goes to the high-impedance state) on the falling edge of TCK.
22
Update-DR
In general, the selected data register is updated with the new data on the falling edge of TCK.
23
Select-DR-Scan
24
Select-IR-Scan
25
Test-Logic-Reset
Test operation completed
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相關代理商/技術參數 |
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| SN74BCT8240ANTE4 | 功能描述:特定功能邏輯 Device w/Octal Inverting Buffers RoHS:否 制造商:Texas Instruments 產品: 系列:SN74ABTH18502A 工作電源電壓:5 V 封裝 / 箱體:LQFP-64 封裝:Tube |
| SN74BCT8244ADW | 功能描述:特定功能邏輯 Device w/Octal Buffers RoHS:否 制造商:Texas Instruments 產品: 系列:SN74ABTH18502A 工作電源電壓:5 V 封裝 / 箱體:LQFP-64 封裝:Tube |
| SN74BCT8244ADWE4 | 功能描述:特定功能邏輯 Device w/Octal Buffers RoHS:否 制造商:Texas Instruments 產品: 系列:SN74ABTH18502A 工作電源電壓:5 V 封裝 / 箱體:LQFP-64 封裝:Tube |
| SN74BCT8244ADWG4 | 功能描述:特定功能邏輯 IEEE Std 1149.1 Bndry Scan Tst Devic RoHS:否 制造商:Texas Instruments 產品: 系列:SN74ABTH18502A 工作電源電壓:5 V 封裝 / 箱體:LQFP-64 封裝:Tube |
| SN74BCT8244ADWR | 功能描述:特定功能邏輯 Device w/Octal Buffers RoHS:否 制造商:Texas Instruments 產品: 系列:SN74ABTH18502A 工作電源電壓:5 V 封裝 / 箱體:LQFP-64 封裝:Tube |
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