TC1910 Datasheet, PDF (45/66 Pages) Infineon Technologies AG – 32-Bit Single-Chip Microcontroller

TC1910
PRELIMINARY
External Oscillator at XTAL1 Timing Requirements
(Operating Conditions apply)
Parameter
Symbol
Limits
Unit
Main Oscillator XTAL frequency¹⁾
Frequency of an external oscillator
driving at XTAL1²⁾
with/without
PLL
with PLL³⁾
without PLL⁴⁾
f_OSC SR
f_OSCDD
SR
min.
4
4
-
max.
16 MHz
25 MHz
25
Input Clock high time
t₁ SR 16
−
ns
Input Clock low time
t₂ SR 16
−
ns
Input Clock rise time
t₃ SR −
7
ns
Input Clock fall time
t₄ SR −
7
ns
1) _{Oscillator Bypass Pin P3.11 latch-in value high. Internal oscillator provides the input clock signal.}
2) _{Oscillator Bypass Pin P3.11 latch-in value low. Internal oscillator disabled. External oscillator provides the input}
clock signal.
3) _{Internal PLL provides the system clock. BYPASS pin latch-in value low. PLL prescaler value P=1.}
4) _{Internal PLL bypassed. BYPASS pin latch-in value high. External oscillator provides the system clock directly.}
When CODEC modules is active its frequency limitations must be taken into consideration. Otherwise,
minimum frequency in this mode can go as low as zero.
t_OSC
Input C lock
at XTAL1
0.5 V _DDOSC
t₁
t₂
t₄
V _IHX
t₃
V _ILX
M CT04882
Figure 12 External Clock at XTAL1 Requirements
Note: V_DDOSC, V_IHX and V_IHL are defined in the Oscillator Pins DC Characteristics
Chapter.
Note: It is strongly recommended to measure the oscillation allowance (negative
resistance) in the final target system (layout) to determine the optimal parameters
for the oscillator operation. Please refer to the limits specified by the crystal
supplier.
Data Sheet
41
V 1.0, 2003-10