SH7032 Datasheet, PDF (83/687 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

Section 4 Exception Handling
4.2.2 Power-On Reset
When the NMI pin is high, a low input at the RES pin drives the chip into the power-on reset state.
The RES pin should be driven low while the clock pulse generator (CPG) is stopped (or while the
CPG is operating during the oscillation settling time) for at least 20 t_cyc to assure that the chip is
reset. A power-on reset initializes the internal state of the CPU and all registers of the on-chip
supporting modules. For pin states in the power-on reset state, see appendix B, Pin States.
While the NMI pin remains high, if the RES pin is held low for a certain time then driven high in
the power-on state, power-on reset exception handling begins. The CPU then:
1. Reads the start address (initial PC value) from the exception vector table.
2. Reads the initial stack pointer value (SP) from the exception vector table.
3. Clears the vector base register (VBR) to H'00000000, and sets interrupt mask bits I3–I0 in the
status register (SR) to H'F (1111).
4. Loads the values read from the exception vector table into the PC and SP and starts program
execution.
A power-on reset must be executed when turning on power.
4.2.3 Manual Reset
When the NMI pin is high, a low input at the RES pin drives the chip into the manual reset state.
To ensure that the chip is properly reset, drive the RES pin low for at least 20 t_cyc. A manual reset
initializes the internal state of the CPU and all registers of the on-chip supporting modules except
the bus state controller, pin function controller, and I/O ports. Since a manual reset does not affect
the bus state controller, the DRAM refresh control function operates even if the manual reset state
continues for a long time. When a manual reset is performed during the bus cycle, manual reset
exception handling is deferred until the end of the bus cycle. The manual reset thus cannot be used
to abort the bus cycle. For the pin states during the manual reset state, see appendix B, Pin States.
While the NMI pin remains low, if the RES pin is held low for a certain time then driven high in
the manual reset state, manual reset exception handling begins. The CPU carries out the same
operations as for a power-on reset.
Rev. 7.00 Jan 31, 2006 page 57 of 658
REJ09B0272-0700