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.
+ 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
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:
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
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.
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
# 6. References
-The NEC protocol is described in these references:
+[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)
-The Philips protocols may be found in these refs:
+Philips protocols:
[RC5](https://en.wikipedia.org/wiki/RC-5)
[RC6](https://www.sbprojects.net/knowledge/ir/rc6.php)
-Sony protocol (future use):
+Sony protocol:
[SIRC](https://www.sbprojects.net/knowledge/ir/sirc.php)
# Appendix 1 NEC Protocol description
projects / micorpython_ir.git / blobdiff