Update ir_rx_test and README re ESP8266 iss 5714.

[micorpython_ir.git] / README.md

diff --git a/README.md b/README.md
index d84bba73e85972385c8e1ab6a752df231d90d216..58cbc9eb97639fc15ff41608b8e9ac4d5861f6f1 100644 (file)
--- a/README.md
+++ b/README.md
@@ -4,6 +4,11 @@ This repo provides a driver to receive from IR (infra red) remote controls and
 a driver for IR "blaster" apps. The device drivers are nonblocking. They do not
 require `uasyncio` but are compatible with it.
 
 a driver for IR "blaster" apps. The device drivers are nonblocking. They do not
 require `uasyncio` but are compatible with it.
 

+NOTE: The receiver is intended to be cross-platform. In testing it has proved
+problematic on ESP8266. The cause is
+[this firmware issue](https://github.com/micropython/micropython/issues/5714)
+which should be fixed in due course.
+

 # 1. IR communication
 
 IR communication uses a carrier frequency to pulse the IR source. Modulation
 # 1. IR communication
 
 IR communication uses a carrier frequency to pulse the IR source. Modulation


@@ -27,10 +32,11 @@ Pyboard.
 
 A remote using the NEC protocol is [this one](https://www.adafruit.com/products/389).
 
 
 A remote using the NEC protocol is [this one](https://www.adafruit.com/products/389).
 

-Remotes normally transmit an address and a data byte. The address denotes the
-physical device being controlled. The data is associated with the button on the
-remote. Provision exists for differentiating between a button repeatedly
-pressed and one which is held down; the mechanism is protocol dependent.
+Remotes transmit an address and a data byte, plus in some cases an extra value.
+The address denotes the physical device being controlled. The data defines the
+button on the remote. Provision usually exists for differentiating between a
+button repeatedly pressed and one which is held down; the mechanism is protocol
+dependent.

 
 # 2. Hardware Requirements
 
 
 # 2. Hardware Requirements
 


@@ -40,14 +46,14 @@ For 38KHz devices a receiver chip such as the Vishay TSOP4838 or the
 [adafruit one](https://www.adafruit.com/products/157) is required. This
 demodulates the 38KHz IR pulses and passes the demodulated pulse train to the
 microcontroller. The tested chip returns a 0 level on carrier detect, but the
 [adafruit one](https://www.adafruit.com/products/157) is required. This
 demodulates the 38KHz IR pulses and passes the demodulated pulse train to the
 microcontroller. The tested chip returns a 0 level on carrier detect, but the

-driver design should ensure operation regardless of sense.
+driver design ensures operation regardless of sense.

 
 In my testing a 38KHz demodulator worked with 36KHz and 40KHz remotes, but this
 
 In my testing a 38KHz demodulator worked with 36KHz and 40KHz remotes, but this

-is obviously not guaranteed or optimal.
+is obviously neither guaranteed nor optimal.

 
 

-The pin used to connect the decoder chip to the target is arbitrary but the
-test programs assume pin X3 on the Pyboard, pin 13 on the ESP8266 and pin 23 on
-ESP32.
+The pin used to connect the decoder chip to the target is arbitrary. The test
+program assumes pin X3 on the Pyboard, pin 23 on ESP32 and pin 13 on ESP8266.
+On the WeMos D1 Mini the equivalent pin is D7.

 
 The transmitter requires a Pyboard 1.x (not Lite) or a Pyboard D. Output is via
 an IR LED which will normally need a transistor to provide sufficient current.
 
 The transmitter requires a Pyboard 1.x (not Lite) or a Pyboard D. Output is via
 an IR LED which will normally need a transistor to provide sufficient current.


@@ -71,10 +77,8 @@ Copy the following files to the target filesystem:
 There are no dependencies.
 
 The demo can be used to characterise IR remotes. It displays the codes returned
 There are no dependencies.
 
 The demo can be used to characterise IR remotes. It displays the codes returned

-by each button. This can aid in the design of receiver applications. When the
-demo runs, the REPL prompt reappears: this is because it sets up an ISR context
-and returns. Press `ctrl-d` to cancel it. A real application would run code
-after initialising reception so this behaviour would not occur.
+by each button. This can aid in the design of receiver applications. The demo
+prints "running" every 5 seconds and reports any data received from the remote.

 
 ## 3.2 Transmitter
 
 
 ## 3.2 Transmitter
 


@@ -110,10 +114,12 @@ Protocol specific args:
  address will be correctly received. Set `False` to enable extra error checking
  for remotes that return an 8 bit address.
  2. `bits=20` Sony specific. The SIRC protocol comes in 3 variants: 12, 15 and
  address will be correctly received. Set `False` to enable extra error checking
  for remotes that return an 8 bit address.
  2. `bits=20` Sony specific. The SIRC protocol comes in 3 variants: 12, 15 and

- 20 bits. The default will handle bitstreams from all three types of remote.
- Choosing a value matching your remote improves the timing and reduces the
- likelihood of errors when handling repeats: the SIRC timing when a button is
- held down is tight in 20 bit mode.
+ 20 bits. The default will handle bitstreams from all three types of remote. A
+ value matching your remote improves the timing and reduces the  likelihood of
+ errors when handling repeats: in 20-bit mode SIRC timing when a button is held
+ down is tight. A worst-case 20-bit block takes 39ms nominal, yet the repeat
+ time is 45ms nominal. On ESP32 20-bit mode did not work well.  
+ The Sony remote tested issues both 12 bit and 15 bit streams.

 
 The callback takes the following args:  
  1. `data` Integer value fom the remote. A negative value indicates an error
 
 The callback takes the following args:  
  1. `data` Integer value fom the remote. A negative value indicates an error


@@ -121,7 +127,9 @@ The callback takes the following args:
  2. `addr` Address from the remote
  3. `ctrl` 0 in the case of NEC. Philips protocols toggle this bit on repeat
  button presses. If the button is held down the bit is not toggled. The
  2. `addr` Address from the remote
  3. `ctrl` 0 in the case of NEC. Philips protocols toggle this bit on repeat
  button presses. If the button is held down the bit is not toggled. The

- transmitter demo implements this behaviour.
+ transmitter demo implements this behaviour.  
+ In the case of Sony the value will be 0 unless receiving a 20-bit stream, in
+ which case it will hold the extended value.

  4. Any args passed to the constructor.
 
 Class variable:  
  4. Any args passed to the constructor.
 
 Class variable:  


@@ -142,7 +150,7 @@ running the chip at 160MHz.
 In general applications should provide user feedback of correct reception.
 Users tend to press the key again if the expected action is absent.
 
 In general applications should provide user feedback of correct reception.
 Users tend to press the key again if the expected action is absent.
 

-Data values passed to the callback are normally positive. Negative values
+Data values passed to the callback are zero or positive. Negative values

 indicate a repeat code or an error.
 
 `REPEAT` A repeat code was received.
 indicate a repeat code or an error.
 
 `REPEAT` A repeat code was received.


@@ -165,8 +173,14 @@ against the check byte. This code is returned on failure.
 # 4.2 Receiver platforms
 
 The NEC protocol has been tested against Pyboard, ESP8266 and ESP32 targets.
 # 4.2 Receiver platforms
 
 The NEC protocol has been tested against Pyboard, ESP8266 and ESP32 targets.

-The Philips protocols - especially RC-6 - have tighter timing constraints. I
-have not yet tested these, but I anticipate problems.
+The Philips protocols - especially RC-6 - have tighter timing constraints.
+Currently the ESP8266 suffers from [this issue](https://github.com/micropython/micropython/issues/5714)
+which prevented testing.
+
+All modes work on the Pyboard. On ESP32 NEC mode works. Sony works for lengths
+of 12 and 15 bits, but 20 bit mode was not reliable owing to the rate at which
+repeats are transmitted. Philips RC-5 worked, with some "bad block" messages.
+Work is ongoing to characterise ESP32 and ESP8266.

 
 # 4.3 Principle of operation
 
 
 # 4.3 Principle of operation
 


@@ -181,7 +195,7 @@ The size of the array and the duration of the timer are protocol dependent and
 are set by the subclasses. The `.decode` method is provided in the subclass.
 
 CPU times used by `.decode` (not including the user callback) were measured on
 are set by the subclasses. The `.decode` method is provided in the subclass.
 
 CPU times used by `.decode` (not including the user callback) were measured on

-a Pyboard D SF2W at stock frequency. They were NEC 1ms for normal data, 100μs
+a Pyboard D SF2W at stock frequency. They were: NEC 1ms for normal data, 100μs

 for a repeat code. Philips codes: RC-5 900μs, RC-6 mode 0 5.5ms.
 
 # 5 Transmitter
 for a repeat code. Philips codes: RC-5 900μs, RC-6 mode 0 5.5ms.
 
 # 5 Transmitter


@@ -202,13 +216,8 @@ All constructors take the following args:
  3. `verbose=False` If `True` emits debug output.
 
 The `SONY` constructor is of form `pin, bits=12, freq=40000, verbose=False`.
  3. `verbose=False` If `True` emits debug output.
 
 The `SONY` constructor is of form `pin, bits=12, freq=40000, verbose=False`.

-The `bits` value may be 12, 15 or 20 to set the highest SIRC variant in use.
-Other args are as above. If `bits` is set to 20 then all variants will be
-received. Setting the value to the maximum expected improves error checking and
-timing tolerances. In particular a worst-case 20-bit block takes 39ms nominal,
-yet the repeat time is 45ms nominal.
-
-The Sony remote tested issues both 12 bit and 15 bit streams.
+The `bits` value may be 12, 15 or 20 to set SIRC variant in use. Other args are
+as above.

 
 Method:
  1. `transmit(addr, data, toggle=0)` Integer args. `addr` and `data` are
 
 Method:
  1. `transmit(addr, data, toggle=0)` Integer args. `addr` and `data` are


@@ -239,7 +248,7 @@ increase power.
 
 The transistor type is not critical.
 
 
 The transistor type is not critical.
 

-These circuits assume circuits as shown. Here the carrier "off" state is 0V,
+The driver assumes circuits as shown. Here the carrier "off" state is 0V,

 which is the driver default. If using a circuit where "off" is required to be
 3.3V, the constant `_SPACE` in `ir_tx.py` should be changed to 100.
 
 which is the driver default. If using a circuit where "off" is required to be
 3.3V, the constant `_SPACE` in `ir_tx.py` should be changed to 100.
 


@@ -256,7 +265,7 @@ channel 1 is used to configure the output pin as a PWM channel. Its frequency
 is set in the constructor. The OOK is performed by dynamically changing the
 duty ratio using the timer channel's `pulse_width_percent` method: this varies
 the pulse width from 0 to a duty ratio passed to the constructor. The NEC
 is set in the constructor. The OOK is performed by dynamically changing the
 duty ratio using the timer channel's `pulse_width_percent` method: this varies
 the pulse width from 0 to a duty ratio passed to the constructor. The NEC

-protocol defaults to 50%, the Philips ones to 30%.
+protocol defaults to 50%, the Sony and Philips ones to 30%.

 
 The duty ratio is changed by the Timer 5 callback `._cb`. This retrieves the
 next duration from the array. If it is not `STOP` it toggles the duty cycle
 
 The duty ratio is changed by the Timer 5 callback `._cb`. This retrieves the
 next duration from the array. If it is not `STOP` it toggles the duty cycle