ds3171n Maxim Integrated Products, Inc., ds3171n Datasheet - Page 214

• Manufacturer Part Number: ds3171n
• Description: Ds3171, Ds3172, Ds3173, Ds3174 Single/dual/triple/quad Ds3/e3 Single-chip Transceivers
• Manufacturer: Maxim Integrated Products, Inc.

CLAMP. All digital output pins output data from the boundary scan parallel output while connecting the bypass
register between JTDI and JTDO. The outputs do not change during the CLAMP instruction. If the previous
instruction was not EXTEST, the outputs will be driven according to the values in the boundary scan register at the
positive edge of JTCLK in the Update-IR state. The typical use of this instruction is in a system that has the JTAG
scan chain of multiple chips connected in series, and all of the chips have their outputs initialized using the
EXTEST mode. Then some of the chips are left initialized using the CLAMP mode and others have their IO
controlled using the EXTEST mode. This reduces the size of the scan chain during the partial testing of the system.
13.4 JTAG ID Codes
Table 13-2. JTAG ID Codes
13.5 JTAG Functional Timing
This functional timing for the JTAG circuits shows:
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•
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Figure 13-3. JTAG Functional Timing
13.6 IO Pins
All input, output, and inout pins are inout pins in JTAG mode.
DS3171
DS3172
DS3173
DS3174
(STATE)
DEVICE
JTRST
Output
JTCLK
(INST)
JTDO
JTMS
The JTAG controller starting from reset state
Shifting out the first 4 LSB bits of the IDCODE
Shifting in the BYPASS instruction (111) while shifting out the mandatory X01 pattern
Shifting the TDI pin to the TDO pin through the bypass shift register
An asynchronous reset occurs while shifting
JTDI
Pin
Reset
X
Consult factory
Consult factory
Consult factory
Consult factory
REVISION
Run Test
ID[31:28]
Idle
Select DR
Scan
Capture
DR
IDCODE
0000000001000100
0000000001000101
0000000001000110
0000000001000111
Shift
DR
DEVICE CODE
X
ID[27:12]
Exit1
DR
Update
DR
Output pin level change if in "EXTEST" instruction mode
Select DR
214
Scan
Select IR
Scan
Capture
MANUFACTURER’S CODE
IR
Shift IR
00010100001
00010100001
00010100001
00010100001
ID[11:1]
X
Exit1
IR
Update
IR
X
Select DR
Scan
Capture
DR
BYPASS
REQUIRED
Shift
DR
ID[0]
1
1
1
1
Logic Idle
X
IDCODE
X
Test