SH7764 Datasheet, PDF (1536/1752 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC Engine Family SH-4A Series

Section 31 User Debugging Interface (H-UDI)
3. This pin should be connected to ground, the PRESET, or another pin which operates in
the same manner as the PRESET pin. However, when connected to a ground pin, the
following problem occurs. Since the TRST pin is pulled up within this LSI, a weak
current flows when the pin is externally connected to ground pin. The value of the
current is determined by a resistance of the pull-up MOS for the port pin. Although this
current does not affect the operation of this LSI, it consumes unnecessary power.
The TCK clock or the CPG of this LSI should be set to ensure that the frequency of the TCK clock
is less than the peripheral-clock frequency of this LSI.
31.3 Boundary Scan TAP Controllers (IDCODE, EXTEST,
SAMPLE/PRELOAD, BYPASS, CLAMP and HIGHZ)
The H-UDI contains two separate TAP controllers: one for controlling the boundary-scan function
and another for controlling the H-UDI reset and interrupt functions. Assertion of TRST, for
example at power-on reset, activates the boundary-scan TAP controller and enables the boundary-
scan function prescribed in the JTAG standards. Executing a switchover command to the H-UDI
allows usage of the H-UDI reset and H-UDI interrupts. This LSI, however, has the following
limitations:
• Clock-related pins (EXTAL and XTAL) are out of the scope of the boundary-scan test.
• Reset-related pin (PRESET) is out of the scope of the boundary-scan test.
• H-UDI-related pins (TCK, TDI, TDO, TMS, TRST and MPMD) are out of the scope of the
boundary-scan test.
• USB-related pins (DM, DP, VBUS, and REFRIN) are out of the scope of the boundary-scan
test
• During the boundary scan (IDCODE, EXTEST, SAMPLE/PRELOAD, BYPASS, CLAMP,
HIGHZ, and H-UDI switchover command), the maximum TCK signal frequency is 2 MHz.
• The external controller has 4-bit access to the boundary-scan TAP controller via the H-UDI.
Note: During the boundary scan, the PRESET pin should be fixed high-level.
Table 31.2 shows the commands supported by the boundary-scan TAP controller.
Rev. 1.00 Nov. 22, 2007 Page 1480 of 1692
REJ09B0360-0100