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PCF85176 - LCD driver in 1:4 mux mode - stopped responding

Question asked by Silas Valera on Aug 13, 2017
Latest reply on Aug 17, 2017 by Silas Valera

Hi 

I am using PCF85176 (TSSOP 56) to drive my custom LCD in 1:4 mux mode. It worked perfectly fine with my setup - chip on my custom PCB and the LCD setup on breadboard - connected using jumper wires. Writing 0x00 and 0xFF to first 15 registers, the display was flashing all segments on/off. But then I realized one of the connection was not correct, and pulling the wires out I accidentally shorted. And now I find that the chip is not responding to the LCD. I can see the I2C signals are fine, the chip is responding on the I2C bus. But the BP signals are not generated.

 

Before I change the PCF85176 for a fresh new one, my question is : is this device so sensitive to short circuit? The reference manual says max +/-10ma, but if I shorted one of the segment driver, that pin should not work, not sure why the chip is not responding at all  Any ideas? I would really appreciate you help..

 

Thanks in advance

Silas 

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