ARM Technical Support Knowledge Articles

PORT PINS P1.2 AND P1.3 CANNOT BE RECONFIGURED

Applies to: EPM900 LPC Emulator

Answer


Information in this article applies to:


QUESTION

The GPIO pins P1.2/P1.3 on the EPM900 Emulator cannot be configured for push-pull or quasi I/O mode. Is there a software update for this?

ANSWER

This problem is present in LPC900 devices (P89LPC901/907/912/914/9102/9103/9107) that do not provide an I2C interface.

Unfortunately, this is a shortcoming of the P89LPC93x bondout device that is used on the EPM900 Emulator/Programmer.

The P89LPC93x bondout chip has an I2C interface on P1.2 and P1.3 and, as such, the pins are configured as open-drain outputs. The mode on these I/O pins is fixed on the bondout device and cannot be changed.

As a workaround you may use external pull-up resistors on this I/O pins. This workaround will show that the ports are working, but does not provide the same current drive characteristics as on the production device.

Article last edited on: 2007-01-12 13:44:29

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