SAB88C166 Datasheet, PDF (36/58 Pages) Siemens Semiconductor Group – 16-Bit CMOS Single-Chip Microcontrollers with/without oscillator prescaler with 32 KByte Flash EPROM

SAB 88C166(W)
AC Characteristics (cont’d)
External Clock Drive XTAL1 for the SAB 88C166W
V_CC = 5 V ± 10 %; V_SS = 0 V
T_A = 0 to + 70 ˚C for SAB 88C166W-M
Parameter
Oscillator period
High time
Low time
Rise time
Fall time
Oscillator duty cycle
Clock cycle
Symbol CPU Clock = 16 MHz Variable CPU Clock Unit
Duty cycle 0.4 to 0.6 1/CLP = 1 to 20 MHz
min.
max.
min.
max.
CLPSR 62.5
62.5
50
1000
ns
TCL_HSR 25
–
25
CLP-TCL_L ns
TCL_LSR 25
–
25
CLP-TCL_H ns
t_RSR
–
10
–
10
ns
t_FSR
–
10
–
10
ns
DCSR 0.4
0.6
25 / CLP
1 – 25 / CLP
TCLSR 25
37.5
CLP x DC_min CLP x DC_max ns
Note: In order to run the SAB 88C166W at a CPU clock of 20 MHz the duty cycle of the oscillator
clock must be 0.5, ie. the relation between the oscillator high and low phases must be 1:1. So
the variation of the duty cycle of the oscillator clock limits the maximum operating speed of
the device.
The 16 MHz values in the tables are given as an example for a typical duty cycle variation of
the oscillator clock from 0.4 to 0.6.
Figure 16
External Clock Drive XTAL1
Semiconductor Group
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