There are only a limited number of ESP GPIO pins available to use, particularly on devices like ESP-01 and Sonoffs modules. But 2 extra GPIOs won't go very far, unless they are utilised for connecting i2c multi-IO Port expanders. This makes it practical to utilise TX and RX as gpio01 and gpio03, as demonstrated in this: TX RX Hack One PCF8574 multi-IO module offers 8 additional ports, which can be configured as Inputs or Outputs. More modules can be added to the i2c bus to increase the available gpio's in banks of 8, ie: 8, 16, 24, 32. Other platforms typically continuously loop to check for change of port input status, so are always 'busy'. Because >Basic is 'event-driven' it can take advantage of interrupts to snooze in between pin changes. This means it can monitor many inputs while doing other tasks and still respond immediately to triggers. User-selectable 3-bit addressing theoretically allows addressing of up to 8 devices.Some like these blue ones are designed to be physically connected into each other. Port direction is software defined, so these could be 16 inputs or 16 outputs or 8 each. And of course other types of i2c modules might also be daisy-chained on the i2c bus. |
Join Our DiscussionCOUNTER |
|
