Boundary Scan (Extest, Sample/Preload, Bypass); Usage Notes - Hitachi SH7751 Hardware Manual

21.3.4

Boundary Scan (EXTEST, SAMPLE/PRELOAD, BYPASS)

The H-UDI pin can be set in the JTAG boundary scan mode by setting a command in SDIR from
the H-UDI. However, in the case of the SH7751 Series, the bypass register (SDBPR) is not
initialized in the Capture-DR state, and the following limitations apply:
1. Clock-related signals (EXTAL, EXTAL2, XTAL, XTAL2, and CKIO) are excluded from the
boundary scan.
2. Reset-related signals (
3. H-UDI signals (TCK, TDI, TDO, TMS, and
4. With EXTEST, 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
elapsed. The clock signal need not be supplied to the EXTAL pin after t
details on t (the power-on oscillation-stabilization time), see section 23, Electrical
OSC1
Characteristics.
6. 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.)
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
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.
Rev. 3.0, 04/02, page 800 of 1064



, , and CA) are excluded from the boundary scan.


pin (Low), negate the
OSC1






) are excluded from the boundary scan.


(the power-on oscillation-stabilization time) has
or the TAP is set in the Test-Logic-Reset state.
pin (High), and assert the
has elapsed. For
OSC1