After a transmission, two receive windows Rx1 and Rx2 are opened
for one second each, one right after the other, after a fixed delay
(for example 5s). The Rx window offset is added to the starting date
of each window and the Rx window duration represents the maximum
delay we will wait for an incoming message before declaring that
a timeout occurred.
A value of -500ms for the offset and 800ms for the duration means
that instead of having Rx1 = [5000, 6000[ and Rx2 = [6000, 7000[
we get Rx1 = [4500, 5300[ and Rx2 = [5500, 6300[. We only cover
30% of the expected windows.
The maximum time a SX127x can take before the Rx side is ready is
TS_HOP + TS_RE = 50µs + 2.33ms. Using 3ms for the offset and
1003ms for the duration will give much better time windows:
Rx1 = [4997, 5997[ and Rx2 = [5997, 7000]. Note that the
lorawan-device crate caps Rx1 end date to Rx2 start date.
This change allows a previously failing Murata CMWX1ZZABZ-091
module (STM32L + SX1276) to connect to the TTN LoRa network.
Call `config()` only once at construction not with every RX and TX operation.
The Lora-E5 only supports HP mode, use that instead.
The nucleo board supports both HP and LP and should continue to work.
The Seeed Studio Lora-E5 module only has two control pins.
With the `RadioSwitch` trait the user can implement any method required
by the module/board to control the TX/RX direction of the radio frontend.
* Interrupt handler only triggers a waker:
Do the actual interrupt processing which involves SUBGHZ SPI coms in the task.
* Do not require a static state for the constructor.
* Remove unsafe from construcor.
It currently contains whoever was first to write some code for the crate,
even if many more people have contributed to it later.
The field is "sort of" deprecated, it was made optional recently:
https://rust-lang.github.io/rfcs/3052-optional-authors-field.html
Due the the reasons listed there I believe removing it is better than
setting it to generic fluff like "The Embassy contributors".
This commit suggests extracting the lora modulation parameters into a
separate function which can then be called from both the do_tx, and
the do_rx functions.
