Error if DIO1 is not on SPI SS pin (Esp32 + RFM95C)

kevin192291 commented 4 years ago

I have an RFM95C connected to an ESP32 and running the arduino-lmic library. Everything works great if I use the pin map:

const lmic_pinmap lmic_pins = {
    .nss = 5,
    .rxtx = LMIC_UNUSED_PIN,
    .rst = 27,
    .dio = {2, 15, 4},
};

Note that .dio[1] is mapped to GPIO15 on my ESP32, this is my SPI SS pin. If i were to move dio1 down just one pin to GPIO8 a standard GPIO pin that is not being used. I get a boot error and loop. I would really really love to free up that SPI SS pin, any ideas as to how to work with this or if not, why the RFM95C requires 2 SPI pins.

The docs do not say anything about requiring GPIO1 to be on a spi port, and dio2 doesn't matter where it is mapped.

Any Ideas?

trlafleur commented 4 years ago

Check the data sheet on the ESP32 to make sure it can be used as an input. There are some restrictions. Also a quick program to read the pin and toggle the led can tell you a lot

On Tue, Jun 16, 2020 at 8:00 AM Kevin notifications@github.com wrote:

I have an RFM95C connected to an ESP32 and running the arduino-lmic library. Everything works great if I use the pin map:

const lmic_pinmap lmic_pins = { .nss = 5, .rxtx = LMIC_UNUSED_PIN, .rst = 27, .dio = {2, 15, 4}, };

Note that .dio[1] is mapped to GPIO15 on my ESP32, this is my SPI SS pin. If i were to move dio1 down just one pin to GPIO8 a standard GPIO pin that is not being used. I get a boot error and loop. I would really really love to free up that SPI SS pin, any ideas as to how to work with this or if not, why the RFM95C requires 2 SPI pins.

The docs do not say anything about requiring GPIO1 to be on a spi port, and dio2 doesn't matter where it is mapped.

Any Ideas?

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matthijskooijman commented 4 years ago

I'm pretty sure this is not something dictated by LMIC, it just needs any I/O pin capable of being used as an input. So as suggested, this is probably an ESP limitation that I can't really help you with, so I'm going to close this. Feel free to continue discussing here, if others do have suggestions.

matthijskooijman / arduino-lmic

Error if DIO1 is not on SPI SS pin (Esp32 + RFM95C) #285