r5f21346mnfp Renesas Electronics Corporation., r5f21346mnfp Datasheet - Page 64

• Manufacturer Part Number: r5f21346mnfp
• Description: Single-chip Mcus Incorporates The R8c Cpu Core
• Manufacturer: Renesas Electronics Corporation.

R8C/34M Group
R01UH0131EJ0100 Rev.1.00
Jun 21, 2011
5.2
5.2.1
5.2.2
A reset is applied using the RESET pin. When an “L” signal is applied to the RESET pin while the supply voltage
meets the recommended operating conditions, pins, CPU, and SFRs are all reset (refer to Table 5.2 Pin Functions
while RESET Pin Level is “L”, Figure 5.2 CPU Register Status after Reset, and Table 4.1 to Table 4.12 SFR
Information).
When the input level applied to the RESET pin changes from “L” to “H”, a program is executed beginning with the
address indicated by the reset vector. After reset, the low-speed on-chip oscillator clock with no division is
automatically selected as the CPU clock.
Refer to 4. Special Function Registers (SFRs) for the states of the SFRs after reset.
The internal RAM is not reset. If the RESET pin is pulled “L” while writing to the internal RAM is in progress, the
contents of internal RAM will be undefined.
Figure 5.4 shows an Example of Hardware Reset Circuit and Operation and Figure 5.5 shows an Example of
Hardware Reset Circuit (Usage Example of External Supply Voltage Detection Circuit) and Operation.
(1) Apply “L” to the RESET pin.
(2) Wait for 10 µs.
(3) Apply “H” to the RESET pin.
(1) Apply “L” to the RESET pin.
(2) Let the supply voltage increase until it meets the recommended operating conditions.
(3) Wait for td(P-R) or more to allow the internal power supply to stabilize (refer to 34. Electrical
(4) Wait for 10 µs.
(5) Apply “H” to the RESET pin.
Hardware Reset
Characteristics).
When Power Supply is Stable
Power On
Page 32 of 740
5. Resets