leonardo46
Italy
Asked
— Edited
Resolved by ptp!
I wish to control LEDs by EZB . I saw in a tutorial leds connected directly to digital outputs without current limiting resistors. The leds I'd use sink 70 mA at 3,3 V . I don't think EZB could withstand such currents ! EZB specs only say the pins are TTL compatible but don't say what's the allowable current (high and low level). What's the allowable current ? I'd add current limiting resistors if necessary. I'd be disappointed burning out my EZB controller.
Hi, everybody. Thanks to Jeremie. EZB specs say: current draw : 80 mA , including everything that's in there (wifi, etc.) with nothing connected to external pins. The current drawn by the MCU itself should be around 30-50 mA (look at the MCU specs). So there is much current to draw from the pins before approaching 120 mA in the MCU itself.
But everybody should remember that this is a stress rating. The chip might be destroyed well before a thermal sensor could protect it. The internal wires in the chip would act as fuseshttps://synthiam.com/emicons/emo_biggrin.gif ! Read MCU specs pages 71-72, ( absolute maximum ratings). The thermal protection will work for the overheathing of the whole chip.
My high luminance leds draw 70 mA @ 3.3 V without limiting resistors, but the internal 330 ohms resistors contained in EZB limit the current to 4 mA only, still producing enough light .https://synthiam.com/emicons/emo_smile.gif bye everybody.