HD6432633 Datasheet, PDF (167/1453 Pages) Renesas Technology Corp – Series of Microcomputers (MCUs: microcomputer units)

Table 4-3 Types of Reset
Type
Conditions for
Transition to Reset
Internal State
MRES RES
CPU
Built-in vicinity module
Power-on reset *
Low
Initialization Initialization
Manual reset Low
High
Initialization Initialization except for bus controller and I/O
port
*: Don't Care
4.2.3 Reset Sequence
This LSI enters reset state when the RES pin or MRES pin goes low.
To ensure that this LSI is reset, hold the RES pin or the MRES pin low for at least 20 ms at power-
up. To reset during operation, hold the RES pin or the MRES pin low for at least 20 states.
When the RES pin or the MRES pin goes high after being held low for the necessary time, this
LSI starts reset exception handling as follows.
1. The internal state of the CPU and the registers of the on-chip supporting modules are
initialized, the T bit is cleared to 0 in EXR, and the I bit is set to 1 in EXR and CCR.
2. The reset exception handling vector address is read and transferred to the PC, and program
execution starts from the address indicated by the PC.
Figures 4-2 and 4-3 show examples of the reset sequence.
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