SH7751 Datasheet, PDF (943/1224 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

21. High-performance User Debug Interface (H-UDI)
21.3.4 Boundary Scan (EXTEST, SAMPLE/PRELOAD, BYPASS)
In this LSI, setting a command from the H-UDI in SDIR can place the H-UDI pins in the
boundary scan mode. However, the following limitations apply.
1. Clock-related signals (EXTAL, EXTAL2, XTAL, XTAL2, and CKIO) are excluded from the
boundary scan.
2. Reset-related signals (RESET, MRESET, and CA) are excluded from the boundary scan.
3. H-UDI signals (TCK, TDI, TDO, TMS, and TRST) are excluded from the boundary scan.
4. With EXTEST, assert the MRESET pin (Low), negate the RESET pin (High), and assert the
CA pin (High). With SAMPLE/PRELOAD, assert the CA pin (High).
5. When executing a boundary scan (EXTEST, SAMPLE/PRELOAD, and BYPASS), supply a
clock signal to the EXTAL pin. The allowed range of input clock frequencies is from 1 to 33.3
MHz. Execute the boundary scan after t_OSC1 (the power-on oscillation-stabilization time) has
elapsed. The clock signal need not be supplied to the EXTAL pin after t_OSC1 has elapsed. For
details on t_OSC1 (the power-on oscillation-stabilization time), see section 23, Electrical
Characteristics.
21.4 Usage Notes
1. SDIR Command
Once an SDIR command is set, it does not change until another command is written from the
H-UDI, unless initialized by asserting TRST or the TAP is set in the Test-Logic-Reset state.
2. SDIR Commands in Sleep Mode
Sleep mode is cleared by an H-UDI interrupt or H-UDI reset, and these exception requests are
accepted in this mode. In standby mode, neither an H-UDI interrupt nor an H-UDI reset is
accepted.
3. In standby mode, the H-UDI function cannot be used. Furthermore, TCK must be retained at a
high level when entering the standby mode in order to retain the TAP state before and after
standby mode.
4. The H-UDI is used for emulator connection. Therefore, H-UDI functions cannot be used when
an emulator is used.
5. When the SH7751 is in bypass mode, the bypass register (SDBPR) is not fixed in the Capture-
DR state. (It is cleared to 0 in the SH7751R.)
Rev.4.00 Oct. 10, 2008 Page 845 of 1122
REJ09B0370-0400