Chapter 20 Extended EJTAG Interface
20-3
20.2.2 Instruction
Register
The JTAG Instruction Register consists of an 8-bit shift register. This register is used for selecting
either one or both of the test to be performed and the Test Data Register to be accessed. The Data
Register is selected according to the instruction code in Table 20.2.1. Refer to the “64-bit TX System
RISC TX49/H2, TX49/H3, TX49/H4 Core Architecture” for more information regarding each
instruction.
Table 20.2.1 Bit Configuration of JTAG Instruction Register
Instruction Code
MSB
→
LSB
Instruction
Selected Data Register
00000000 (0x00)
EXTEST
Boundary Scan Register
00000001 (0x01)
SAMPLE/PRELOAD
Boundary Scan Register
00000010 (0x02)
Reserved
Reserved
00000011 (0x03)
IDCODE
Device ID Register
00000100 - 00001111
Reserved
Reserved
00010000 (0x10)
HIGHZ
Bypass Register
00010001 - 01111111
Reserved
Reserved
10000000 - 11111110
Refer to the “64-bit TX System RISC TX49/H2, TX49/H3, TX49/H4 Core Architecture”
11111111 (0xFF)
BYPASS
Bypass Register
Figure 20.2.1 shows the format of the Instruction Register.
7 6 5 4 3 2 1 0
MSB
LSB
Figure 20.2.1 Instruction Register
The instruction code is shifted to the Instruction Register starting from the Least Significant Bit.
LSB
TDO
TDI
MSB
Figure 20.2.2 Shift Direction of the Instruction Register
20.2.3 Boundary Scan Register
The Boundary Scan Register contains a single 391-bit shift register to which all TX4937 I/O signals
except for power supply, TDI, TCK, TDO, TMS, TRST*, and TEST[4]* are connected. Figure 20.2.3 shows
the bits of the Boundary Scan Register.
390 0
Refer to TX4937 BSDL file
Figure 20.2.3 Boundary Scan Register
TDI input is fetched to the Most Significant Bit (MSB) of the Boundary Scan Register and the Least
Significant Bit (LSB) of the Boundary Scan Register is sent from the TDO output.
Table 20.2.2 shows the boundary scan sequence relative to the processor signals.
Summary of Contents for TX49 TMPR4937
Page 1: ...64 Bit TX System RISC TX49 Family TMPR4937 Rev 2 0 ...
Page 4: ......
Page 13: ...Table of Contents ix TMPR4937 Revision History 1 ...
Page 14: ...Table of Contents x ...
Page 15: ...Handling Precautions ...
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Page 18: ...1 Using Toshiba Semiconductors Safely 1 2 ...
Page 40: ...3 General Safety Precautions and Usage Considerations 3 18 ...
Page 42: ...4 Precautions and Usage Considerations 4 2 ...
Page 43: ...TMPR4937 2005 3 Rev 2 0 ...
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Page 52: ...Chapter 1 Overview and Features 1 6 ...
Page 156: ...Chapter 7 External Bus Controller 7 56 ...
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Page 530: ...Chapter 22 Pinout and Package Information 22 10 ...
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