SH7280 Datasheet, PDF (1524/1726 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine family

Section 28 Power-Down Modes
28.1.2 Reset
A reset is used when the power is turned on or to run the LSI again from the initialized state.
There are two types of reset: power-on reset and manual reset. In a power-on reset, all the ongoing
processing is halted and any unprocessed events are canceled, and the reset processing starts
immediately. On the other hand, a manual reset does not interrupt processing to retain external
memory data. Conditions for generating a power-on reset or manual reset are as follows:
(1) Power-On Reset
1. A low level is input to the RES pin.
2. The watchdog timer (WDT) starts counting with the WT/IT bit in WTCSR set to 1 and with
the RSTS bit in WRCSR set to 0 while the RSRE bit in WRCSR is 1, and the counter
overflows.
3. The H-UDI reset is generated (for details on the H-UDI reset, see section 29, User
Debugging Interface (H-UDI)).
(2) Manual Reset
1. A low level is input to the MRES pin.
2. The WDT starts counting with the WT/IT bit in WTCSR set to 1 and with the RSTS bit in
WRCSR set to 1 while the RSRE bit in WRCSR is 1, and the counter overflows.
Rev. 1.00 Jun. 26, 2008 Page 1494 of 1692
REJ09B0393-0100