SH7203 Datasheet, PDF (1466/1686 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 29 User Debugging Interface (H-UDI)
29.5 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, all of the functions in the H-UDI
cannot be used. To retain the TAP status before and after standby mode, keep TCK high before
entering standby mode.
3. Regardless of whether or not the H-UDI is in use, be sure to keep the TRST pin low to
initialize the H-UDI when power is supplied or when assertion of the RES signal cancels deep
standby mode.
4. When the TDO change timing switch command is set and the TRST pin is asserted
immediately after and the RES pin is negated, the TDO change timing switch command may
be cleared. To prevent this, make sure to insert an interval of 20 t_cyc or more between the signal
changes of the RES and TRST pins when the TDO change timing switch command is set.
Make sure to put 20 t_cyc or more between the signal change timing of the RES and TRST pins.
For details, see 29.4.3, TDO Output Timing.
5. When starting the TAP controller after the negation of the TRST pin, make sure to allow 200
ns or more after the negation.
Rev. 2.00 Apr. 16, 2008 Page 1436 of 1652
REJ09B0313-0200