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参数资料
| 型号： | SCANPSC100FDMQB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 微控制器/微处理器 |
| 英文描述： | SPECIALTY MICROPROCESSOR CIRCUIT, CDIP28 |
| 封装： | CERAMIC, DIP-28 |
| 文件页数： | 9/27页 |
| 文件大小： | 381K |
| 代理商： | SCANPSC100FDMQB |
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Serial Scan Interface (SSI) (Continued)
Figure 14 shows a block diagram of the Linear Feedback
Shift Register hookup.
The SSC is loaded by two PPI writes to the TDI address.
When the SSC enable bit is set, a pulse is issued internally
that initializes the local parallel load logic such that the SSC
is loaded sequentially, most significant byte first, least sig-
nificant byte last. When in SSC mode, writes can be com-
pleted at any time; however, shift operations will be disabled
until the SSC is fully loaded. PPI reads from TDI are ignored
while in SSC mode.
Upon leaving SSC mode an internal pulse causes the TDI
shifter/buffer to be full. Also, local read select logic is initial-
ized such that the signature is read most-significant byte
first.
TEST LOOP-BACK MODES. This feature provides a means
for testing ’PSC100 functionality by looping data appearing
at the output of an outgoing shifter/buffer (i.e., TMS0, TMS1
or TDO) back to the input of the TDI shifter/buffer. The loop
back function is accomplished with a simple multiplexer (see
Figure 13) whose path selection is determined by setting the
mode bits in MODE1(1:0). Loop back does not disable TCK
or prevent shifting of data in the shifter/buffers to the scan
chain(s) connected to the PSC100. Therefore, the state and
operation of the TAP controllers within the scan chain(s)
must be considered when developing Loop-Back test vec-
tors to prevent undesired shifting of data or TAP controller
transitions within the scan chain.
32-BIT COUNTER (CNT32)
CNT32 is a 32-bit, count-down binary counter arranged in
four 8-bit segments. CNT32 can be loaded independent of
its enable/disable status. Loading requires four consecutive
writes to its address (least significant byte first). These four
writes must
not be interleaved with writes to any other ad-
dress or the CNT32 write control logic will be re-initialized.
This re-initialization will result in a partially filled counter with
an undesired
value. CNT32 is reset each time the counter
hits terminal count or by asserting the RST pin. A synchro-
nous reset condition (setting Mode2(1)) does not reset the
counter and a new value must be written to CNT32 to
provide the desired number of TCK cycles.
SINGLE STEP MODE: All four 8-bit registers are readable
for testability; however, there are no update latches similar to
the ones used for the status bits. To stabilize the counter for
read operations during on-board test, the Single Step Mode
has been added. This allows the user to place CNT32 in any
state and then count for one SCK cycle (TCK will not toggle
when in singled step mode). The result can then be read
from the PPI. The counter can be tested by loading it with
values at its boundary conditions, and then clocking for one
cycle to see the results. For example, the counter could be
loaded with the value:
00000001
00000000
The next step is to set the Single Step Mode bit so that the
counter counts down to the next state and stops. The next
value is:
00000000
11111111
Four read cycles using the PPI will reveal the results of the
test.
Note: CNT32 will not wrap from terminal count (i.e., 00000000h decremented
by 1 will remain unchanged and will not wrap to FFFFFFFFh). There-
fore, CNT32 should be loaded with a non-zero value prior to a Single
Step Mode Operation.
TIMING WAVEFORMS
10032515
FIGURE 15. Serial Scan Interface Timing
SCANPSC100F
Embedded
www.national.com
17
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SCANPSC100FLMQB | 制造商:Texas Instruments 功能描述: |
| SCANPSC100FSC | 功能描述:接口 - 专用 Emb Boun Scan Cont RoHS:否 制造商:Texas Instruments 产品类型:1080p60 Image Sensor Receiver 工作电源电压:1.8 V 电源电流:89 mA 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:BGA-59 |
| SCANPSC100FSCX | 功能描述:接口 - 专用 Emb Boun Scan Cont RoHS:否 制造商:Texas Instruments 产品类型:1080p60 Image Sensor Receiver 工作电源电压:1.8 V 电源电流:89 mA 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:BGA-59 |
| SCANPSC110 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:SCAN Bridge Hierarchical and Multidrop Addressable JTAG Port (IEEE1149.1 System Test Support) |
| SCANPSC110_ZFC3026B WAF | 制造商:Fairchild Semiconductor Corporation 功能描述: |
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