H8S18 Datasheet, PDF (508/758 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2200 Series

Section 13 Boundary Scan Function
13.3 Register Descriptions
The boundary scan function has the following registers. These registers cannot be accessed by the
CPU.
• Instruction register (INSTR)
• IDCODE register (IDCODE)
• BYPASS register (BYPASS)
• Boundary scan register (BSCANR)
13.3.1 Instruction Register (INSTR)
INSTR is a 3-bit register. At initialization, this register is specified to IDCODE mode. When
TRST is pulled low, or when the TAP controller is in the Test-Logic-Reset state, INSTR is
initialized. INSTR can be written by the serial data input from the TDI. If more than three bits of
instruction is input from the TDI, INSTR stores the last three bits of serial data.
If a command reserved in INSTR is used, the correct operation cannot be guaranteed.
Bit Bit Name Initial Value R/W Description
2 TI2
1
1 TI1
0
—
Test Instruction Bits
—
Instruction configuration is shown in table 13.2.
0 TI0
1
—
Table 13.2 Instruction Configuration
Bit 2 Bit1
TI2
TI1
0
0
0
0
0
1
0
1
1
0
1
0
1
1
1
1
Bit 0
TI0
0
1
0
1
0
1
0
1
Instruction
EXTEST
SAMPLE/PRELOAD
CLAMP
HIGHZ
Reserved
IDCODE (initial value)
Reserved
BYPASS
Rev.7.00 Dec. 24, 2008 Page 452 of 698
REJ09B0074-0700