National CP3BT26 User Manual
247
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CP3
BT26
30.6
OUTPUT SIGNAL LEVELS
All output signals are powered by the digital supply (VCC).
Table 83 summarizes the states of the output signals during
the reset state (when VCC power exists in the reset state)
and during the Power Save mode.
the reset state (when VCC power exists in the reset state)
and during the Power Save mode.
The RESET and NMI input pins are active during the Power
Save mode. In order to guarantee that the Power Save cur-
rent not exceed 1 mA, these inputs must be driven to a volt-
age lower than 0.5V or higher than VCC - 0.5V. An input
voltage between 0.5V and (VCC - 0.5V) may result in power
consumption exceeding 1 mA.
Save mode. In order to guarantee that the Power Save cur-
rent not exceed 1 mA, these inputs must be driven to a volt-
age lower than 0.5V or higher than VCC - 0.5V. An input
voltage between 0.5V and (VCC - 0.5V) may result in power
consumption exceeding 1 mA.
30.7
CLOCK AND RESET TIMING
Table 83
Output Pins During Reset and Power-Save
Signals on a Pin
Reset State
(with Vcc)
Power Save Mode
Comments
PB7:0
TRI-STATE
Previous state
I/O ports will maintain their values when
entering power-save mode
entering power-save mode
PC7:0
TRI-STATE
Previous state
PE5:0
TRI-STATE
Previous state
PF7:0
TRI-STATE
Previous state
PG7:0
TRI-STATE
Previous state
PH7:0
TRI-STATE
Previous state
PJ7:0
TRI-STATE
Previous state
Table 84
Clock and Reset Signals
Symbol Figure
Description
Reference
Min (ns)
Max (ns)
Clock Input Signals
t
X1p
X1 period
Rising Edge (RE) on X1 to
next RE on X1
next RE on X1
83.33
83.33
t
X1h
X1 high time, external clock
At 2V level (Both Edges)
(0.5 Tclk) - 5
t
X1l
X1 low time, external clock
At 0.8V level (Both Edges)
(0.5 Tclk) - 5
t
X2p
X2 period
a
RE on X2 to next RE on X2
10,000
t
X2h
X2 high time, external clock
At 2V level (both edges)
(0.5 Tclk) - 500
t
X2l
X2 low time, external clock
At 0.8V level (both edges)
(0.5 Tclk) - 500
t
IH
Input hold time (NMI, RXD1, RXD2)
After RE on CLK
0
Reset and NMI Input Signals
t
IW
NMI Pulse Width
NMI Falling Edge (FE) to
RE
RE
20
t
RST
RESET Pulse Width
RESET FE to RE
100
t
R
Vcc Rise Time
0.1 Vcc to 0.9 Vcc
a. Only when operating with an external square wave on X2CKI; otherwise a 32 kHz crystal network must be
used between X2CKI and X2CKO. If Slow Clock is internally generated from Main Clock, it may not exceed
this given limit.
this given limit.