Renesas M16C FAMILY series Hardware Manual page 57

M 1 6 C 2 / 8 G o r u p ( M 1 6 C
Low Voltage Detection Interrupt Register
b 7 b 6 b 5 b 4
NOTES:
1. Write to this register after setting the PRC3 bit in the PRCR register to "1" (write enable).
2. Useful when the VC27 bit in the VCR2 register is set to "1" (low voltage detection circuit enabled). If the
VC27 bit is set to "0" (low voltage detection circuit disable), the D42 bit is set to "0" (Not detect).
3. This bit is set to "0" by writing a "0" in a program. (Writing a "1" has no effect.)
4. If the low voltage detection interrupt needs to be used to get out of stop mode again after once used for that
purpose, reset the D41 bit by writing a "0" and then a "1".
5. The D40 bit is effective when the VC27 bit in the VCR2 register is set to "1". To set the D40 bit to "1", follow
the procedure described below.
(1) Set the VC27 bit to "1".
(2) Wait for td(E-A) until the detection circuit is actuated.
(3) Wait for the sampling time (refer to Table 5.3 Sampling Clock Periods).
(4) Set the D40 bit to "1".
Figure 5.6 D4INT Register
VCC
RESET
Internal Reset Signal
VC13 bit in
VCR1 register
VC26 bit in
(1)
VCR2 register
VC27 bit in
VCR2 register
NOTES :
1. VC26 bit is invalid in stop mode. (the microcomputer is not reset even if input voltage of VCC pin
becomes lower than Vdet3).
Figure 5.7 Typical Operation of Brown-out Detection Reset (Hardware Reset 2)
R e . v 2 0 . 0 J a . n 3 , 1 2 0 0 7
R E J 0 9 B 0 0 4 7 0 - 2 0 0
2 / , 8 M 1 6 C 2 / 8 ) B
b 3 b 2 b 1 b 0
S y m b o l
D 4 I N T
B i t S y m b o l
Low voltage detection
D 4 0
interrupt enable bit
STOP mode deactivation
D 4 1
control bit
Voltage change detection flag
D 4 2
(2)
WDT overflow detect flag
D43
Sampling clock select bit
DF0
D F 1
Nothing is assigned. When write, set to "0". When read, its
(b7-b6)
content is "0".
5.0V
Vdet4
Vdet3r
Vdet3
Vdet3s
VSS
Indeterminate
Indeterminate
Indeterminate
page 37
f o 3 8 5
(1)
A d d r e s s A f t e r R e s e t
0 0 1 F 0 0
1 6 1 6
Bit Name
Disable
0 :
(5)
Enable
1 :
0 : D i s a b l e ( d o n o t u s e t h e l o w
v o l t a g e d e t e c t i o n i n t e r r u p t t o e x i t
(4)
s t o p m o d e )
1 : E n a b l e ( u s e t h e l o w v o l t a g e
d e t e c t i o n i n t e r r u p t t o e x i t s t o p
m o d e )
0: Not detected
1: Vdet4 passing detection
0 : N o t d e t e c t e d
1 : D e t e c t e d
b 5b4
0 0 : C P U c l o c k d i v i d e d b y 8
0 1 : C P U c l o c k d i v i d e d b y 1 6
1 0 : C P U c l o c k d i v i d e d b y 3 2
1 1 : C P U c l o c k d i v i d e d b y 6 4
Set to "1" by program (reset level detect circuit enable)
Set to "1" by program
(low voltage detection circuit enable)
RW
Function
RW
RW
RW
( 3 )
RW
( 3 )
R W
R W
5.0V
5. Reset