Renesas SH7781 - Manual (Page 1533)

30. User Debugging Interface (H-UDI)
Rev.1.00 Jan. 10, 2008 Page 1503 of 1658
REJ09B0261-0100
30.4 Operation
30.4.1 Boundary-Scan TAP Controller (IDCODE, EXTEST, SAMPLE/PRELOAD, and
BYPASS)
In the H-UDI in this LSI, the boundary-scan TAP controller is separated from the TAP controller
for other H-UDI function control. When the
TRST is asserted (including when the power is turned
on), the boundary-scan TAP controller operates and the boundary scan function specified in JTAG
can be used. By inputting the switching command, an H-UDI reset and H-UDI interrupts can be
used. However, the following restrictions are put on this LSI.
• 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, AUDSYNC, AUDCK, AUDATA3 to
AUDATA0, and MPMD) are out of the scope of the boundary scan test.
• DDRIF-related pins are out of the scope of the boundary scan test.
• During the boundary scan (IDCODE, EXTEST, SAMPLE/PRELOAD, BYPASS, and H-UDI
switching command), the maximum frequency of TCK is 10 MHz.
• The access size from the H-UDI to the boundary-scan TAP controller is 8 bits.
The commands supported by the boundary-scan TAP controller are shown below.
Note: During the boundary scan, the MPMD and the
PRESET pins should be fixed to high level.
When the H-UDI operates in emulation support mode (MPMD = 0), the boundary scan
function cannot be used. Figure 30.2 shows the sequence to switch from the boundary-
scan TAP controller to the H-UDI.
Table 30.6 Commands Supported by Boundary-Scan TAP Controller
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Description
0 1 0 1 0 1 0 1 IDCODE
1 1 1 1 1 1 1 1 BYPASS
0 0 0 0 0 0 0 0 EXTEST
0 1 0 0 0 0 0 0 SAMPLE/PRELOAD
0 0 0 0 1 0 0 0 H-UDI switching command
Other than above Setting prohibited