Update RadioDriver.md docs

doc/RadioDriver.md

@@ -13,17 +13,23 @@
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+- [Radio Driver Operation](#radio-driver-operation)
+	- [`os_radio(RADIO_RST)`](#os_radioradio_rst)
+	- [`os_radio(RADIO_TX)`](#os_radioradio_tx)
+	- [`os_radio(RADIO_RX)`](#os_radioradio_rx)
+	- [`os_radio(RADIO_RXON)`](#os_radioradio_rxon)
 - [Common parameters](#common-parameters)
 	- [`LMIC.rps` (IN)](#lmicrps-in)
 	- [`LMIC.freq` (IN)](#lmicfreq-in)
 	- [`LMIC.saveIrqFlags` (OUT)](#lmicsaveirqflags-out)
+	- [`LMIC.osjob` (IN/OUT)](#lmicosjob-inout)
 - [Transmit parameters](#transmit-parameters)
 	- [`LMIC.radio_txpow` (IN)](#lmicradio_txpow-in)
 	- [`LMIC.frame[]` (IN)](#lmicframe-in)
 	- [`LMIC.datalen` (IN)](#lmicdatalen-in)
 	- [`LMIC.txend` (OUT)](#lmictxend-out)
 - [Receive parameters](#receive-parameters)
-	- [LMIC.frame[] (OUT)](#lmicframe-out)
+	- [`LMIC.frame[]` (OUT)](#lmicframe-out)
 	- [`LMIC.datalen` (OUT)](#lmicdatalen-out)
 	- [`LMIC.rxtime` (IN/OUT)](#lmicrxtime-inout)
 	- [`LMIC.lbt_ticks` (IN)](#lmiclbt_ticks-in)
@@ -37,6 +43,34 @@
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+## Radio Driver Operation
+
+The LMIC radio driver operates asynchronously. Operations are started by calling the `os_radio()` function with a parameter describing the operation to be performed.
+
+Various parameters in the LMIC structure are as input to control the operation; others are updated to return results.
+
+### `os_radio(RADIO_RST)`
+
+The radio is reset, and put to sleep. This operation is synchronous.
+
+### `os_radio(RADIO_TX)`
+
+A frame is transmitted. The parameters are given in [common parameters](#common-parameters) and [transmit parameters](#transmit-parameters).
+
+When the operation completes, `LMIC.osjob` is scheduled.
+
+### `os_radio(RADIO_RX)`
+
+A single frame is received ad the specified time, and the radio is put back to sleep if no frame is found.
+
+When the operation completes, `LMIC.osjob` is scheduled.
+
+### `os_radio(RADIO_RXON)`
+
+The radio is placed in continuous receive mode. If a frame is received, `LMIC.osjob` is scheduled. Continuous receive is canceled by calling [`os_radio(RADIO_RST)`](#os_radioradio_rst).
+
+This operation is not supported in FSK mode.
+
 ## Common parameters
 
 ### `LMIC.rps` (IN)
@@ -57,6 +91,10 @@ This specifies the frequency, in Hertz.
 
 Updated for LoRa operations only; the IRQ flags at the time of interrupt.
 
+### `LMIC.osjob` (IN/OUT)
+
+When asynchronous operations complete, `LMIC.osjob.func` is used as the callback function, and `LMIC.osjob` is used to schedule the work.
+
 ## Transmit parameters
 
 ### `LMIC.radio_txpow` (IN)
@@ -77,9 +115,9 @@ The OS time at which the TX end interrupt was recognized.
 
 ## Receive parameters
 
-### LMIC.frame[] (OUT)
+### `LMIC.frame[]` (OUT)
 
-Filled with data received..
+Filled with data received.
 
 ### `LMIC.datalen` (OUT)
 
@@ -89,7 +127,7 @@ Set to number of bytes received in total.
 
 Input: When to start receiving, in OS tick time.
 
-Output: time of RXDONE interrupt.  (FSK timeout doesn't currently set.)
+Output: time of RXDONE interrupt. (Note: FSK timeout doesn't currently set this cell on RX timeout.)
 
 ### `LMIC.lbt_ticks` (IN)
 
@@ -101,7 +139,7 @@ Maximum RSSI on channel before transmit.
 
 ### `LMIC.rxsyms` (IN)
 
-The timeout in symbols.
+The timeout in symbols. Only used for `os_radio(RADIO_RX)`; not used for continuous receive.
 
 ### `LMIC.noRXIQinversion` (IN)