Philips LPC2129 - Figure 13: FOSC Selection Algorithm

System Control Block 68 May 03, 2004
Philips Semiconductors Preliminary User Manual
LPC2119/2129/2194/2292/2294ARM-based Microcontroller
Figure 13: F
OSC
selection algorithm
5 - 10 MHz
10 pF < 300 : 18 pF, 18 pF
20 pF < 300 : 38 pF, 38 pF
30 pF < 300 : 58 pF, 58 pF
10 - 15 MHz
10 pF < 300 : 18 pF, 18 pF
20 pF < 220 : 38 pF, 38 pF
30 pF < 140 : 58 pF, 58 pF
15 - 20 MHz
10 pF < 220 : 18 pF, 18 pF
20 pF < 140 : 38 pF, 38 pF
30 pF < 80 : 58 pF, 58 pF
20 - 25 MHz
10 pF < 160 : 18 pF, 18 pF
20 pF < 90 : 38 pF, 38 pF
30 pF < 50 : 58 pF, 58 pF
25 - 30 MHz
10 pF <130 : 18 pF, 18 pF
20 pF <50 : 38 pF, 38 pF
30 pF n.a. n.a.
Table 13: Recommended values for C
X1/X2
in oscillation mode (crystal and external components parameters)
Fundamental Oscillation
Frequency F
C
Crystal Load
Capacitance C
L
Max. Crystal Series
Resistence R
S
External Load
Capacitors C
X1
, C
X2
f
OSC
selection
min f
OSC
= 10 MHz
max f
OSC
= 25 MHz
True
True
min f
OSC
= 1 MHz
max f
OSC
= 30 MHz
True
min f
OSC
= 1 MHz
max f
OSC
= 50 MHz
on-chip PLL used
in application?
ISP used for initial
code download?
external crystal
oscillator used?
False
False
False
(Figure 12, mode a and/or b) (Figure 12, mode a) (Figure 12, mode b)