
R8C/36T-A Group
28. Electrical Characteristics
Under development Preliminary document
Specifications in this document are tentative and subject to change.
R01UH0240EJ0010 Rev.0.10
Page 675 of 728
Aug 05, 2011
Note:
1. To use the power-on reset function, enable voltage monitor 0 reset by setting the LVDAS bit in the OFS register to 0.
Figure 28.3
Power-on Reset Circuit Characteristics
Notes:
1. This enables the setting errors of bit rates such as 9600 bps and 38400 bps to be 0% when the serial interface is used in
UART mode.
2. This indicates the precision error for the oscillation frequency of the high-speed on-chip oscillator.
Table 28.10
Power-On Reset Circuit Characteristics (1) (Measurement conditions: Vcc = 1.8 V to 5.5 V, Topr =
20°C to 85°C (N version)/
40°C to 85°C (D version))
Symbol
Parameter
Conditions
Standard
Unit
Min.
Typ.
Max.
trth
External power VCC rise gradient
0
―
50,000
mV/msec
Table 28.11
High-Speed On-Chip Oscillator Circuit Characteristics
Symbol
Parameter
Conditions
Standard
Unit
Min.
Typ.
Max.
―
High-speed on-chip oscillator frequency
after reset
Vcc = 1.8 V to 5.5 V,
20°C Topr 85°C
(N version)
40°C Topr 85°C
(D version)
―
40
―
MHz
High-speed on-chip oscillator frequency
when 01b or 10b is written to bits
FRA25 and FRA24 in the FRA2 register
—
36.864
—
MHz
High-speed on-chip oscillator frequency
when 10b is written to bits FRA25 and
FRA24 in the FRA2 register
—32—
MHz
High-speed on-chip oscillator frequency
dependence on temperature and power
1.5
―
1.5
%
―
Oscillation stability time
Vcc = 5.0 V, Topr = 25°C
―
250
―μs
―
Self power consumption at oscillation
Vcc = 5.0 V, Topr = 25°C
―
500
―μA
Notes:
1. Vdet0 indicates the voltage detection level of the voltage detection 0 circuit. Refer to the Voltage Detection
Circuit chapter for details.
2. tw(por) indicates the duration the external power VCC must be held below the valid voltage (0.5 V) to enable
a power-on reset. When turning on the power after it falls with voltage monitor 0 reset disabled, maintain
tw(por) for 1 ms or more.
Vdet0
(1)
0.5 V
Internal
reset signal
tw(por)
(2)
Voltage detection 0
circuit response time
Vdet0
(1)
1
fOCO-S
32
1
fOCO-S
32
External
Power VCC
trth