Pinout and Hardware Design Notes
The following pinout is used in the RapidHA Lighting firmware. The Z357PA40 module pad numbers are shown in brackets:
| Z357PA40 Module Pad | EM357 Pin | Function |
|---|---|---|
| 5 | PB3 | Relay Out |
| 6 | PB4 | PWM Out |
| 9 | PA5* | Network LED |
| 15 | PB2 | Zigbee Serial RX |
| 16 | PA6 | Button |
| 17 | PB1 | Zigbee Serial TX |
*A transistor circuit is required to ensure that this pin is held high at startup. This pin assignment will be changing. See the note below for more information.
PA5 Protection Circuit
Pin PA5 on the EM357 has a built-in function defined by Silicon Labs; if it is held low at startup, the EM357 will enter bootload mode. MMB is in the process of updating the pinout to use a different pin that is available on our new Z357PA40 module. Until the new firmware implementing a different pinout is released, it is necessary to add the “protection circuit” shown below. R1 and R2 must have the same resistance.
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