XC228X Datasheet, PDF (93/110 Pages) Infineon Technologies AG – 16/32-Bit Single-Chip Microcontroller with 32-Bit Performance

XC2287 / XC2286 / XC2285
XC2000 Family Derivatives
Preliminary
Electrical Parameters
4.4.3 External Clock Drive
These parameters define the external clock supply for the XC228x. The clock signal can
be supplied either to pin P2.9 or to pin XTAL1.
Table 19 External Clock Drive Characteristics (Operating Conditions apply)
Parameter
Symbol
Limit Values
Unit
Min.
Max.
Oscillator period
t_OSC
SR 25
250¹⁾
ns
High time²⁾
t₁
SR 6
–
ns
Low time²⁾
t₂
SR 6
–
ns
Rise time²⁾
t₃
SR –
8
ns
Fall time²⁾
t₄
SR –
8
ns
1) The maximum limit is only relevant for PLL operation to ensure the minimum input frequency for the PLL.
2) The clock input signal must reach the defined levels V_ILC and V_IHC (for XTAL1) or V_IL and V_IH for P2.9.
t₁
0.5 V_DDI
t₃
t₂
t _OSC
t₄
V _IHC
V _ILC
MCT05572
Figure 16 External Clock Drive XTAL1
Note: If the on-chip oscillator is used together with a crystal or a ceramic resonator, the
oscillator frequency is limited to a range of 4 MHz to 16 MHz.
It is strongly recommended to measure the oscillation allowance (negative
resistance) in the final target system (layout) to determine the optimum
parameters for the oscillator operation. Please refer to the limits specified by the
crystal supplier.
When driven by an external clock signal it will accept the specified input frequency
range. Operation at input frequencies below 4 MHz is possible but is verified by
design only (not subject to production test).
Data Sheet
91
V0.91, 2007-02
Draft Version