README Add warning re concurrent receive on ESP32.

[micorpython_ir.git] / README.md

diff --git a/README.md b/README.md
index 2eb3a47f35bbe7760bbc3cb6288f4ea8538efd5e..48259c5f25034e06ae3c675d27b87bae22be717c 100644 (file)
--- a/README.md
+++ b/README.md
@@ -5,8 +5,22 @@ a driver for IR "blaster" apps. The device drivers are nonblocking. They do not
 require `uasyncio` but are compatible with it, and are designed for standard
 firmware builds.
 
 require `uasyncio` but are compatible with it, and are designed for standard
 firmware builds.
 

-The receiver is cross platform and has been tested on Pyboard, ESP8266 and
-ESP32.
+The receiver is cross platform and has been tested on Pyboard, ESP8266, ESP32
+and Raspberry Pi Pico.
+
+In a typical use case the receiver is employed at the REPL to sniff the address
+and data values associated with buttons on a remote control. The transmitter is
+then used in an application to send those codes, emulating the remote control.
+
+Other use cases involve running the receiver in an application. This enables an
+IR remote to control a device such as a robot. This may be problematic on some
+platforms. Please see [section 4](./README.md#4-receiver-limitations).
+
+## Raspberry Pi Pico note
+
+Early firmware has [this issue](https://github.com/micropython/micropython/issues/6866)
+affecting USB communication with some PC's. This is now fixed. Please ensure
+you are using up to date firmware.

 
 #### [Receiver docs](./RECEIVER.md)
 
 
 #### [Receiver docs](./RECEIVER.md)
 


@@ -81,22 +95,32 @@ proprietary protocols and are not supported by these drivers.
 | Samsung   | 38    | Measured      | N       |
 | Panasonic | 36.3  | Measured      | N       |
 
 | Samsung   | 38    | Measured      | N       |
 | Panasonic | 36.3  | Measured      | N       |
 

-# 4. References
+# 4. Receiver limitations
+
+The receiver uses a pin interrupt and depends on a quick response to a state
+change on the pin. This is guaranteed on platforms which support hard IRQ's
+such as the Pyboard and the RP4 Pico. The ESP32 and ESP8266 only support soft
+IRQ's. This means that, if code such as WiFi communication is running
+concurrently, reliable reception may be problematic.
+
+# 5. References

 
 

-Sources of information about IR protocols.  
+Sources of information about IR protocols. The `sbprojects.net` site is an
+excellent resource.  

 [General information about IR](https://www.sbprojects.net/knowledge/ir/)
 
 The NEC protocol:  
 [altium](http://techdocs.altium.com/display/FPGA/NEC+Infrared+Transmission+Protocol)  
 [circuitvalley](http://www.circuitvalley.com/2013/09/nec-protocol-ir-infrared-remote-control.html)
 [General information about IR](https://www.sbprojects.net/knowledge/ir/)
 
 The NEC protocol:  
 [altium](http://techdocs.altium.com/display/FPGA/NEC+Infrared+Transmission+Protocol)  
 [circuitvalley](http://www.circuitvalley.com/2013/09/nec-protocol-ir-infrared-remote-control.html)

+[sbprojects.net](https://www.sbprojects.net/knowledge/ir/nec.php)

 
 Philips protocols:  
 
 Philips protocols:  

-[RC5](https://en.wikipedia.org/wiki/RC-5)  
-[RC5](https://www.sbprojects.net/knowledge/ir/rc5.php)  
-[RC6](https://www.sbprojects.net/knowledge/ir/rc6.php)
+[RC5 Wikipedia](https://en.wikipedia.org/wiki/RC-5)  
+[RC5 sbprojects.net](https://www.sbprojects.net/knowledge/ir/rc5.php)  
+[RC6 sbprojects.net](https://www.sbprojects.net/knowledge/ir/rc6.php)

 
 Sony protocol:  
 
 Sony protocol:  

-[SIRC](https://www.sbprojects.net/knowledge/ir/sirc.php)
+[SIRC sbprojects.net](https://www.sbprojects.net/knowledge/ir/sirc.php)

 
 MCE protocol:  
 [OrtekMCE](http://www.hifi-remote.com/johnsfine/DecodeIR.html#OrtekMCE)
 
 MCE protocol:  
 [OrtekMCE](http://www.hifi-remote.com/johnsfine/DecodeIR.html#OrtekMCE)