| .. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later |
| |
| .. _Remote_controllers_Protocols: |
| |
| ***************************************** |
| Remote Controller Protocols and Scancodes |
| ***************************************** |
| |
| IR is encoded as a series of pulses and spaces, using a protocol. These |
| protocols can encode e.g. an address (which device should respond) and a |
| command: what it should do. The values for these are not always consistent |
| across different devices for a given protocol. |
| |
| Therefore out the output of the IR decoder is a scancode; a single u32 |
| value. Using keymap tables this can be mapped to linux key codes. |
| |
| Other things can be encoded too. Some IR protocols encode a toggle bit; this |
| is to distinguish whether the same button is being held down, or has been |
| released and pressed again. If has been released and pressed again, the |
| toggle bit will invert from one IR message to the next. |
| |
| Some remotes have a pointer-type device which can used to control the |
| mouse; some air conditioning systems can have their target temperature |
| target set in IR. |
| |
| The following are the protocols the kernel knows about and also lists |
| how scancodes are encoded for each protocol. |
| |
| rc-5 (RC_PROTO_RC5) |
| ------------------- |
| |
| This IR protocol uses manchester encoding to encode 14 bits. There is a |
| detailed description here https://www.sbprojects.net/knowledge/ir/rc5.php. |
| |
| The scancode encoding is *not* consistent with the lirc daemon (lircd) rc5 |
| protocol, or the manchester BPF decoder. |
| |
| .. flat-table:: rc5 bits scancode mapping |
| :widths: 1 1 2 |
| |
| * - rc-5 bit |
| |
| - scancode bit |
| |
| - description |
| |
| * - 1 |
| |
| - none |
| |
| - Start bit, always set |
| |
| * - 1 |
| |
| - 6 (inverted) |
| |
| - 2nd start bit in rc5, re-used as 6th command bit |
| |
| * - 1 |
| |
| - none |
| |
| - Toggle bit |
| |
| * - 5 |
| |
| - 8 to 13 |
| |
| - Address |
| |
| * - 6 |
| |
| - 0 to 5 |
| |
| - Command |
| |
| There is a variant of rc5 called either rc5x or extended rc5 |
| where there the second stop bit is the 6th commmand bit, but inverted. |
| This is done so it the scancodes and encoding is compatible with existing |
| schemes. This bit is stored in bit 6 of the scancode, inverted. This is |
| done to keep it compatible with plain rc-5 where there are two start bits. |
| |
| rc-5-sz (RC_PROTO_RC5_SZ) |
| ------------------------- |
| This is much like rc-5 but one bit longer. The scancode is encoded |
| differently. |
| |
| .. flat-table:: rc-5-sz bits scancode mapping |
| :widths: 1 1 2 |
| |
| * - rc-5-sz bits |
| |
| - scancode bit |
| |
| - description |
| |
| * - 1 |
| |
| - none |
| |
| - Start bit, always set |
| |
| * - 1 |
| |
| - 13 |
| |
| - Address bit |
| |
| * - 1 |
| |
| - none |
| |
| - Toggle bit |
| |
| * - 6 |
| |
| - 6 to 11 |
| |
| - Address |
| |
| * - 6 |
| |
| - 0 to 5 |
| |
| - Command |
| |
| rc-5x-20 (RC_PROTO_RC5X_20) |
| --------------------------- |
| |
| This rc-5 extended to encoded 20 bits. The is a 3555 microseconds space |
| after the 8th bit. |
| |
| .. flat-table:: rc-5x-20 bits scancode mapping |
| :widths: 1 1 2 |
| |
| * - rc-5-sz bits |
| |
| - scancode bit |
| |
| - description |
| |
| * - 1 |
| |
| - none |
| |
| - Start bit, always set |
| |
| * - 1 |
| |
| - 14 |
| |
| - Address bit |
| |
| * - 1 |
| |
| - none |
| |
| - Toggle bit |
| |
| * - 5 |
| |
| - 16 to 20 |
| |
| - Address |
| |
| * - 6 |
| |
| - 8 to 13 |
| |
| - Address |
| |
| * - 6 |
| |
| - 0 to 5 |
| |
| - Command |
| |
| |
| jvc (RC_PROTO_JVC) |
| ------------------ |
| |
| The jvc protocol is much like nec, without the inverted values. It is |
| described here https://www.sbprojects.net/knowledge/ir/jvc.php. |
| |
| The scancode is a 16 bits value, where the address is the lower 8 bits |
| and the command the higher 8 bits; this is reversed from IR order. |
| |
| sony-12 (RC_PROTO_SONY12) |
| ------------------------- |
| |
| The sony protocol is a pulse-width encoding. There are three variants, |
| which just differ in number of bits and scancode encoding. |
| |
| .. flat-table:: sony-12 bits scancode mapping |
| :widths: 1 1 2 |
| |
| * - sony-12 bits |
| |
| - scancode bit |
| |
| - description |
| |
| * - 5 |
| |
| - 16 to 20 |
| |
| - device |
| |
| * - 7 |
| |
| - 0 to 6 |
| |
| - function |
| |
| sony-15 (RC_PROTO_SONY15) |
| ------------------------- |
| |
| The sony protocol is a pulse-width encoding. There are three variants, |
| which just differ in number of bits and scancode encoding. |
| |
| .. flat-table:: sony-12 bits scancode mapping |
| :widths: 1 1 2 |
| |
| * - sony-12 bits |
| |
| - scancode bit |
| |
| - description |
| |
| * - 8 |
| |
| - 16 to 23 |
| |
| - device |
| |
| * - 7 |
| |
| - 0 to 6 |
| |
| - function |
| |
| sony-20 (RC_PROTO_SONY20) |
| ------------------------- |
| |
| The sony protocol is a pulse-width encoding. There are three variants, |
| which just differ in number of bits and scancode encoding. |
| |
| .. flat-table:: sony-20 bits scancode mapping |
| :widths: 1 1 2 |
| |
| * - sony-20 bits |
| |
| - scancode bit |
| |
| - description |
| |
| * - 5 |
| |
| - 16 to 20 |
| |
| - device |
| |
| * - 7 |
| |
| - 0 to 7 |
| |
| - device |
| |
| * - 8 |
| |
| - 8 to 15 |
| |
| - extended bits |
| |
| nec (RC_PROTO_NEC) |
| ------------------ |
| |
| The nec protocol encodes an 8 bit address and an 8 bit command. It is |
| described here https://www.sbprojects.net/knowledge/ir/nec.php. Note |
| that the protocol sends least significant bit first. |
| |
| As a check, the nec protocol sends the address and command twice; the |
| second time it is inverted. This is done for verification. |
| |
| A plain nec IR message has 16 bits; the high 8 bits are the address |
| and the low 8 bits are the command. |
| |
| nec-x (RC_PROTO_NECX) |
| --------------------- |
| |
| Extended nec has a 16 bit address and a 8 bit command. This is encoded |
| as a 24 bit value as you would expect, with the lower 8 bits the command |
| and the upper 16 bits the address. |
| |
| nec-32 (RC_PROTO_NEC32) |
| ----------------------- |
| |
| nec-32 does not send an inverted address or an inverted command; the |
| entire message, all 32 bits, are used. |
| |
| For this to be decoded correctly, the second 8 bits must not be the |
| inverted value of the first, and also the last 8 bits must not be the |
| inverted value of the third 8 bit value. |
| |
| The scancode has a somewhat unusual encoding. |
| |
| .. flat-table:: nec-32 bits scancode mapping |
| |
| * - nec-32 bits |
| |
| - scancode bit |
| |
| * - First 8 bits |
| |
| - 16 to 23 |
| |
| * - Second 8 bits |
| |
| - 24 to 31 |
| |
| * - Third 8 bits |
| |
| - 0 to 7 |
| |
| * - Fourth 8 bits |
| |
| - 8 to 15 |
| |
| sanyo (RC_PROTO_SANYO) |
| ---------------------- |
| |
| The sanyo protocol is like the nec protocol, but with 13 bits address |
| rather than 8 bits. Both the address and the command are followed by |
| their inverted versions, but these are not present in the scancodes. |
| |
| Bis 8 to 20 of the scancode is the 13 bits address, and the lower 8 |
| bits are the command. |
| |
| mcir2-kbd (RC_PROTO_MCIR2_KBD) |
| ------------------------------ |
| |
| This protocol is generated by the Microsoft MCE keyboard for keyboard |
| events. Refer to the ir-mce_kbd-decoder.c to see how it is encoded. |
| |
| mcir2-mse (RC_PROTO_MCIR2_MSE) |
| ------------------------------ |
| |
| This protocol is generated by the Microsoft MCE keyboard for pointer |
| events. Refer to the ir-mce_kbd-decoder.c to see how it is encoded. |
| |
| rc-6-0 (RC_PROTO_RC6_0) |
| ----------------------- |
| |
| This is the rc-6 in mode 0. rc-6 is described here |
| https://www.sbprojects.net/knowledge/ir/rc6.php. |
| The scancode is the exact 16 bits as in the protocol. There is also a |
| toggle bit. |
| |
| rc-6-6a-20 (RC_PROTO_RC6_6A_20) |
| ------------------------------- |
| |
| This is the rc-6 in mode 6a, 20 bits. rc-6 is described here |
| https://www.sbprojects.net/knowledge/ir/rc6.php. |
| The scancode is the exact 20 bits |
| as in the protocol. There is also a toggle bit. |
| |
| rc-6-6a-24 (RC_PROTO_RC6_6A_24) |
| ------------------------------- |
| |
| This is the rc-6 in mode 6a, 24 bits. rc-6 is described here |
| https://www.sbprojects.net/knowledge/ir/rc6.php. |
| The scancode is the exact 24 bits |
| as in the protocol. There is also a toggle bit. |
| |
| rc-6-6a-32 (RC_PROTO_RC6_6A_32) |
| ------------------------------- |
| |
| This is the rc-6 in mode 6a, 32 bits. rc-6 is described here |
| https://www.sbprojects.net/knowledge/ir/rc6.php. |
| The upper 16 bits are the vendor, |
| and the lower 16 bits are the vendor-specific bits. This protocol is |
| for the non-Microsoft MCE variant (vendor != 0x800f). |
| |
| |
| rc-6-mce (RC_PROTO_RC6_MCE) |
| --------------------------- |
| |
| This is the rc-6 in mode 6a, 32 bits. The upper 16 bits are the vendor, |
| and the lower 16 bits are the vendor-specific bits. This protocol is |
| for the Microsoft MCE variant (vendor = 0x800f). The toggle bit in the |
| protocol itself is ignored, and the 16th bit should be takes as the toggle |
| bit. |
| |
| sharp (RC_PROTO_SHARP) |
| ---------------------- |
| |
| This is a protocol used by Sharp VCRs, is described here |
| https://www.sbprojects.net/knowledge/ir/sharp.php. There is a very long |
| (40ms) space between the normal and inverted values, and some IR receivers |
| cannot decode this. |
| |
| There is a 5 bit address and a 8 bit command. In the scancode the address is |
| in bits 8 to 12, and the command in bits 0 to 7. |
| |
| xmp (RC_PROTO_XMP) |
| ------------------ |
| |
| This protocol has several versions and only version 1 is supported. Refer |
| to the decoder (ir-xmp-decoder.c) to see how it is encoded. |
| |
| |
| cec (RC_PROTO_CEC) |
| ------------------ |
| |
| This is not an IR protocol, this is a protocol over CEC. The CEC |
| infrastructure uses rc-core for handling CEC commands, so that they |
| can easily be remapped. |
| |
| imon (RC_PROTO_IMON) |
| -------------------- |
| |
| This protocol is used by Antec Veris/SoundGraph iMON remotes. |
| |
| The protocol |
| describes both button presses and pointer movements. The protocol encodes |
| 31 bits, and the scancode is simply the 31 bits with the top bit always 0. |
| |
| rc-mm-12 (RC_PROTO_RCMM12) |
| -------------------------- |
| |
| The rc-mm protocol is described here |
| https://www.sbprojects.net/knowledge/ir/rcmm.php. The scancode is simply |
| the 12 bits. |
| |
| rc-mm-24 (RC_PROTO_RCMM24) |
| -------------------------- |
| |
| The rc-mm protocol is described here |
| https://www.sbprojects.net/knowledge/ir/rcmm.php. The scancode is simply |
| the 24 bits. |
| |
| rc-mm-32 (RC_PROTO_RCMM32) |
| -------------------------- |
| |
| The rc-mm protocol is described here |
| https://www.sbprojects.net/knowledge/ir/rcmm.php. The scancode is simply |
| the 32 bits. |
| |
| xbox-dvd (RC_PROTO_XBOX_DVD) |
| ---------------------------- |
| |
| This protocol is used by XBox DVD Remote, which was made for the original |
| XBox. There is no in-kernel decoder or encoder for this protocol. The usb |
| device decodes the protocol. There is a BPF decoder available in v4l-utils. |
