In my testing a 38KHz demodulator worked with 36KHz and 40KHz remotes, but this
is obviously neither guaranteed nor optimal.
+The TSOP4838 can run from 3.3V or 5V supplies. The former should be used on
+non-5V compliant hosts such as ESP32 and Raspberry Pi Pico and is fine on 5V
+compliant hosts too.
+
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.
+program `acquire.py` uses the following pins by default:
+
+| Host | Pin | Notes |
+|:-------:|:---:|:-----:|
+| Pyboard | X3 | |
+| ESP32 | 23 | |
+| ESP8266 | 13 | |
+| D1 Mini | D7 | WeMos name for pin 13. |
+| Pico | 16 | |
A remote using the NEC protocol is [this one](https://www.adafruit.com/products/389).
from ir_rx.acquire import test
test()
```
-This script is under development.
-
-It waits for a single burst from the remote and prints the timing of the pulses
-followed by its best guess at the protocol. It correctly identifies supported
-protocols, but can wrongly identify some unsupported proprietary protocols.
+This script waits for a single burst from the remote and prints the timing of
+the pulses followed by its best guess at the protocol. It correctly identifies
+supported protocols, but can wrongly identify unsupported protocols. The
+report produced by the script exposed to an unknown protocol is unpredictable.
+The `test()` function returns a list of the mark and space periods (in μs).
# 3. The driver
1. These are constants defining the NEC repeat code and the error codes sent
to the error function. They are discussed in [section 4](./RECEIVER.md#4-errors).
-#### NEC classes
+#### NEC classes (includes Samsung)
-`NEC_8`, `NEC_16`
+`NEC_8`, `NEC_16`, `SAMSUNG`
Typical invocation:
```python
address: the complement is checked and the address returned as an 8-bit value.
A 16-bit address will result in an error.
+The `SAMSUNG` class returns 16 bit address and data values. The remote sample
+tested did not issue repeat codes - if a button is held down it simply repeated
+the original value. In common with other NEC classes the callback receives a
+value of 0 in the `ctrl` arg.
+
+Thanks are due to J.E.Tannenbaum for information about the Samsung protocol.
+
#### Sony classes
`SONY_12`, `SONY_15`, `SONY_20`
from ir_rx.philips import RC5_IR
```
-These support the RC-5 and RC-6 mode 0 protocols respectively.
+These support the RC-5 (including RC-5X) and RC-6 mode 0 protocols
+respectively.
+
+#### Microsoft MCE class
+
+`MCE`
+
+Typical invocation:
+```python
+from ir_rx.mce import MCE
+```
+
+I have been unable to locate a definitive specification: the protocol was
+analysed by a mixture of googling and experiment. Behaviour may change if I
+acquire new information. The protocol is known as OrtekMCE and the remote
+control is sold on eBay as VRC-1100.
+
+The remote was designed for Microsoft Media Center and is used to control Kodi
+on boxes such as the Raspberry Pi. With a suitable PC driver it can emulate a
+PC keyboard and mouse. The mouse emulation uses a different protocol: the class
+does not currently support it. Pressing mouse buttons and pad will cause the
+error function (if provided) to be called.
+
+Args passed to the callback comprise 4 bit `addr`, 6 bit `data` and 2 bit `ctrl`
+with the latter having the value 0 for the first message and 2 for the message
+sent on key release. Intermediate messages (where the key is held down) have
+value 1.
+
+There is a 4-bit checksum which is used by default. The algorithm requires an
+initial 'seed' value which my testing proved to be 4. However the only
+[documentation](http://www.hifi-remote.com/johnsfine/DecodeIR.html#OrtekMCE) I
+could find stated that the value should be 3. I implemented this as a class
+variable `MCE.init_cs=4`. This enables it to be changed if some remotes use 3.
+If the value is set to -1 the check will be skipped.
# 4. Errors
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.
-# 7. 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)
-
-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)
+# 7. Unsupported protocols
-Sony protocol:
-[SIRC](https://www.sbprojects.net/knowledge/ir/sirc.php)
+It is possible to capture an IR burst from a remote and to re-create it using
+the transmitter. This has limitations and is discussed in detail in
+[the transmitter doc](./TRANSMITTER.md#5-unsupported-protocols).
# Appendix 1 NEC Protocol description
burst is constant, giving a constant burst length of 67.5ms. In extended
address mode this constancy is lost. The burst length can (by my calculations)
run to 76.5ms.
+
+# Appendix 2 MCE Protocol
+
+The bitstream comprises a header (2ms mark, 1ms space) followed by 16 bits of
+Manchester encoded data with a bit time of 500μs. Data are encoded
+```
+ccccddddddppaaaa
+```
+Where `aaaa` is the address, `pp` is the position (toggle) field, `dddddd` is
+data and `cccc` is a checksum. This is calculated by counting the ones in
+`ddddddppaaaa` and adding 4. Data are transmitted LSB first.
+
+The only [doc](http://www.hifi-remote.com/johnsfine/DecodeIR.html#OrtekMCE) I
+could find states that the checksum seed value is 3, but this did not match the
+remote I have.
projects / micorpython_ir.git / blobdiff