Philips PAB90 1 Series Getting Started Manual page 17

• Crystal Oscillator socket
Different Crystal oscillator values can be tested for the LPC901 in socket Y1.
To use an external crystal, FlashMagic offers you to reprogram UCFG1, the
User-Configuration Register of the LPC90x devices
(ISP | Device Configuration):
Please note: Only LPC901 features external crystal pin inputs. LPC902 and
LPC903 can only be run from the internal RC oscillator or the internal
Watchdog oscillator.
Please note: The capacitors C2 and C3 are the capacitors belonging to the
crystal oscillator circuit. These capacitors are just recommendations. Since
many factors play a role in oscillator circuits (board design, board layout,
tolerances of components etc.), it is HIGHLY RECOMMENDED to do
extensive testing of the oscillator circuit in your own hardware to make sure
your oscillator circuitry works reliably under different conditions like
temperature and voltage.
• Access to LPC90x port pins:
The header rows J3 and J4 provide access to the 8 port pins of the LPC90x
(see next page).
PAB90x-1 Getting Started V1.0 Page 17