Differences

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--- esp8266_gpio_pin_allocations [2017/10/30 08:09]
dampmaskin [PWM] correction
+++ esp8266_gpio_pin_allocations [2017/11/10 02:12]
ekriirke [LED Pin] no comments on IO1/TX being low affecting boot process
@@ Line 116: / Line 116: @@
 ===== LED Pin =====
-GPIO1, which is also TX, is wired to the blue LED on many devices.  Note that the LED is active low (connected to Vcc and sinks through the chip to ground) so setting a logical value of 0 will light it up.  Since GPIO1 is also the TX pin, you won't be able to blink the LED and perform Serial communications at thew same time unless you switch TX/RX pins.
+GPIO1, which is also TX, is wired to the blue LED on many devices.  Note that the LED is active low (connected to Vcc and sinks through the chip to ground) so setting a logical value of 0 will light it up.  Since GPIO1 is also the TX pin, you won't be able to blink the LED and perform Serial communications at the same time unless you switch TX/RX pins.
+Note that if this pin is pulled LOW on power up, the ESP will not boot. (The normal LED is from Vcc to IO1, an LED from GND to IO1 is enough to prevent boot)
 ===== Maximum Current =====