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5. Evaluating the P89LPC90x using PAB90x-1
As described in section 4, the user code that has been programmed using
PAB90x-1 + MCB900 can be run and PAB90x-1 can now be used as a small
stand-alone board to evaluate the user software. The following elements are
available for evaluation:
• LED:
PAB90x-1 provides one low-active green LED (D1) that can be hooked up to
any port pin of the LPC90x. A LOW level at the LED header pin turns the
LED on, a HIGH level turns it off.
• Potentiometer:
PAB90x-1 provides a potentiometer, which delivers 0V to 3.3V to the V_AN
("analog voltage") header pin. This analog voltage can directly be fed to the
on-chip comparator on the LCP90x or the header pins V_C and
RC_CHARGE can be used to do a slope conversion Analog-to-Digital
Converter (together with resistor R2 and capacitor C4). This slope
conversion ADC is described in detail in Application Note AN10187,
"Low-cost A/D-Conversion with Philips LPC Microcontrollers". This
Application Note (among others) is included on the CD.
• Push Button:
A push button (PB) is provided as an external trigger in an application or to
wake up the LPC90x from Power-Down mode using the keyboard interrupt
feature. If header pin KBI is hooked up to a port pin in quasi-bidirectional
mode (providing an internal pull-up resistor), the level at the port pin will be
HIGH if the button is not pressed. It will go LOW when the button is pressed.
Please note that the button might "bounce", so you might get several
transitions at the port pin.
PAB90x-1 Getting Started V1.0
Page 16
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