M16C26 Datasheet, PDF (25/239 Pages) Renesas Technology Corp – 16-BIT CMOS SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/20 SERIES

Udenvdeelropment
Preliminary Specifications Rev. 0.9
Specifications in this manual are tentative and subject to change.
Reset
M16C/26 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
2. Limitations on wait instructions with peripheral clocks turned off
If the WAIT instruction is executed when bit VC13 of the VCR1 register is equal to “1” (VCC ³
VDET4), bit VC27 of the VCR2 register is equal to “1” (VDET4 detection circuit enabled), and bit D40
of the D4INT register is equal to “1” (VDET4 detection interrupt enabled), a VDET4 detection interrupt
is immediately generated, causing the microcomputer to exit from wait mode.
In systems where the microcomputer enters wait mode when the input voltage in the VCC pin drops
under VDET4 and exits from wait mode when the input voltage goes over VDET4, ensure that the
WAIT instruction is executed when VC13 = “0” (VCC < VDET4).
VDET4 detect circuit
VDET4 detect interrupt generation circuit
VC27
DF1, DF0
002
012
102
BCLK 1/8
1/2
1/2
112
1/2
VC13
VCC
VREF
+
Noise
-
rejection
(Rejection wide:200 ns)
VDET4 detect
signal
H when VC27
bit= 0 (disabled)
Noise rejection
circuit
Digital
filter
D41
D42 bit is cleared to 0 (not
detected) by writing a 0 in a
program. VC27 bit is cleared to
0 (VDET4 detection circuit
disabled), the D42 bit is set to
0.
D42
watchdog
timer interrupt
signal
VDET4 detect
interrupt signal
CM02
WAIT instruction(wait mode)
Watchdog timer block
D43
Watchdog timer
overflow signal
This bit is cleared to 0 (not detected) by writing a 0 in a program.
D40
Oscillation stop
detection
interrupt signal
Non-maskable
interrupt signal
Figure 1.5.8. VDET4 detection interrupt generation block
VCC
VC13 bit
sampling
sampling
sampling
sampling
Output of the digital filter (Note 2)
D42 bit
VDET4 detect interrupt signal
(Note 1)
No VDET4 detection interrupt signals are generated
when the D42 bit is H .
Set to 0 in a
program (not
detected)
Set to 0 in a
program (not
detected)
Note 1 : D40 is 1 (VDET4 detect interrupt enabled)
Note 2 : Output of the digital filter shown in Figure 1.5.8.
Figure 1.5.9. VDET4 detection interrupt generation circuit operation example
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Renesas Technology Corp.