M32C8A Datasheet, PDF (58/372 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M32C/80 Series

M32C/8A Group
6. Power Supply Voltage Detection Function
6.1 Vdet3 Detection Function
The hardware reset 2 is performed if the voltage applied to the VCC1 pin drops to Vdet3 (V) or below.
Set the VC26 bit in the VCR2 register to 1 to use this Vdet3 detection function.
When the hardware reset 2 occurs, ports and I/O pins for peripheral functions are reset. The CPU and SFRs are
reset when td(S-R) elapses after the voltage applied to the VCC1 pin reaches Vdet3r (V) or above. Then, the MCU
executes a program in an address indicated by the reset vector. The states of pins and SFRs after reset are the same
as the hardware reset 1.
Use the Vdet3 detection function while operating at or above Vdet3s. If the applied voltage drops below Vdet3s,
perform the hardware reset 1 (refer to 5.1.1 Reset at a Stable Supply Voltage). The Vdet3 detection function
cannot be used while the MCU is in stop mode.
Figure 6.5 shows a Vdet3 detection function operation example.
VCC1
Vdet3r
Vdet3
Vdet3s
2.0V⁽²⁾
VSS
5.0 V
3.0 V⁽¹⁾
3.1 V⁽¹⁾
5.0 V
RESET
VC26 bit in the
VCR2 register
Internal reset signal
“H”
“L”
“1”
Undefined
“0”
“H”
“L”
NOTES:
1. Typical value.
2. Minimum value.
Set to 1 (Vdet3 detection function used) by program.
Wait time to release
hardware reset 2: td(S-R)
Figure 6.5 Vdet3 Detection Function Operation Example
Rev.1.00 Jul 15, 2007 Page 41 of 352
REJ09B0385-0100