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Topic: TX light stays on (do I need to program a new FTDI chip?) (Read 1 time) previous topic - next topic

robotman777

I am testing a clone of an arduino I made for a personal project that essentially used the deuminalove pcb layout/parts/schematic as the basis.

Everything powers up and the FTDI chip can be ready by my computer. However, the TX light stays stuck on the pcb and I am unable to send or receive serial messages from my arduino.

I bought the FTDI chip new from Mouser. Do I need to program the eeprom on it?

tim7

Does it stay lit if you remove the ATmega chip?  The FTDI chip should not need programming, and if your PC recognises it that's a good sign.  It could be that the AVR chip has its serial pins configured as high outputs, forcing the serial LEDs on.

retrolefty

Quote
It could be that the AVR chip has its serial pins configured as high outputs, forcing the serial LEDs on.


No, the FTDI uses different pins for the rx/tx leds then the signal lines it uses for tx/rx to the AVR chip. They are not electrically connected and do not simple reflect the electrical value of the pins 0 and 1 state.


Lefty

robotman777

yeah the TX light stays on whether a atmega is plugged in or not.

However, I did notice that the problem seems to occur when powering off of the USB jack. When I am powering from external source it is not staying on.

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