m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 47

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

RESET
3.1 Reset operation
There are 3 ways to reset the microcomputer:
3.1 Reset operation
Operations of hardware, software, and power-on reset are described below.
3-2
Fig. 3.1.1 Example of hardware reset timing
3.1.1 Hardware reset
Figure 3.1.1 shows an example of hardware reset timing.
The following explains how the microcomputer operates in the above periods,
ten cycles of f
(Refer to section “3.3 State of internal area.”)
Internal processing sequence after reset.”)
vector addresses (addresses FFFE
After applying “L” level of voltage to pin RESET, the microcomputer initializes pins within a period of several
The microcomputer initializes the central processing unit (CPU) and SFR area in the following periods.
After
The microcomputer executes a program beginning with the address which has been set into the reset
Hardware reset : Apply “L” level of voltage to pin RESET while the power source voltage (Vcc) meets
Software reset : Write “1” to the software reset bit (bit 6 at address 5E
Power-on reset : After power-on, raise the voltage level at pin Vcc to the level, which meets the
• While pin RESET is at “L” level.
• In the period of 8 to 9 cycles of f
Note: The above is applied when the oscillator is stably oscillating or when an
RESET
, the microcomputer performs “Internal processing sequence after reset.” (Refer to section “3.4
external clock is stably input from pin X
oscillating (including the case at the stop mode’s termination; refer to section
“15.3 Stop mode.”), apply “L” level of voltage for 10 s or more after the
oscillation becomes stable.
sys
. (Refer to section “3.2 Pin state.”)
the recommended operating conditions.
voltage (Vcc) meets the recommended operating conditions.
recommend operating conditions, with “L” level of voltage applied to pin RESET.
10 s or more
(Note)
7905 Group User’s Manual Rev.1.0
16
and FFFF
sys
8 to 9 cycles of f
after pin RESET goes from “L” to “H.”
16
).
IN.
When the oscillator is not stably
Internal processing
sequence after
reset
sys
Program is executed.
16
) while the power source
to
.