SH7205 Datasheet, PDF (1632/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 31 User Debugging Interface (H-UDI)
31.7 Usage Notes
1. An H-UDI command, once set, will not be modified as long as another command is not set
again from the H-UDI. If the same command is to be set continuously, the command must be
set after a command (BYPASS mode, etc.) that does not affect chip operations is once set.
2. In software standby mode and H-UDI module standby state, none of the functions in the H-
UDI can be used. To retain the TAP status before and after standby mode, keep TCK high
before entering standby mode.
3. Regardless of whether the H-UDI is used, make sure to keep the TRST pin low to initialize the
H-UDI at power-on or in recovery from deep standby by the RES pin assertion.
4. If the TRST pin is asserted immediately after the setting of the TDO transition timing
switching command and the negation of the RES pin, the TDO transition timing switching
command is cleared. To avoid this case, make sure to put 20 tcyc or longer between the signal
transition timing of the RES and TRST pins. For details, see section 31.5.3, TDO Output
Timing.
5. When starting the TAP controller after the negation of the TRST pin, make sure to allow 200
ns or longer after the negation.
Rev. 1.00 Mar. 25, 2008 Page 1600 of 1868
REJ09B0372-0100