lookup table for converting NEC commands/addresses to the esphome32 remote_transmitter.transmit_nec format

nec_util.h

#ifndef UTIL_H

#define UTIL_H
int nec_format(unsigned char b) {
  static const int nec_code_table[256] = {
      0x00ff, 0x807f, 0x40bf, 0xc03f, 0x20df, 0xa05f, 0x609f, 0xe01f, 0x10ef,
      0x906f, 0x50af, 0xd02f, 0x30cf, 0xb04f, 0x708f, 0xf00f, 0x08f7, 0x8877,
      0x48b7, 0xc837, 0x28d7, 0xa857, 0x6897, 0xe817, 0x18e7, 0x9867, 0x58a7,
      0xd827, 0x38c7, 0xb847, 0x7887, 0xf807, 0x04fb, 0x847b, 0x44bb, 0xc43b,
      0x24db, 0xa45b, 0x649b, 0xe41b, 0x14eb, 0x946b, 0x54ab, 0xd42b, 0x34cb,
      0xb44b, 0x748b, 0xf40b, 0x0cf3, 0x8c73, 0x4cb3, 0xcc33, 0x2cd3, 0xac53,
      0x6c93, 0xec13, 0x1ce3, 0x9c63, 0x5ca3, 0xdc23, 0x3cc3, 0xbc43, 0x7c83,
      0xfc03, 0x02fd, 0x827d, 0x42bd, 0xc23d, 0x22dd, 0xa25d, 0x629d, 0xe21d,
      0x12ed, 0x926d, 0x52ad, 0xd22d, 0x32cd, 0xb24d, 0x728d, 0xf20d, 0x0af5,
      0x8a75, 0x4ab5, 0xca35, 0x2ad5, 0xaa55, 0x6a95, 0xea15, 0x1ae5, 0x9a65,
      0x5aa5, 0xda25, 0x3ac5, 0xba45, 0x7a85, 0xfa05, 0x06f9, 0x8679, 0x46b9,
      0xc639, 0x26d9, 0xa659, 0x6699, 0xe619, 0x16e9, 0x9669, 0x56a9, 0xd629,
      0x36c9, 0xb649, 0x7689, 0xf609, 0x0ef1, 0x8e71, 0x4eb1, 0xce31, 0x2ed1,
      0xae51, 0x6e91, 0xee11, 0x1ee1, 0x9e61, 0x5ea1, 0xde21, 0x3ec1, 0xbe41,
      0x7e81, 0xfe01, 0x01fe, 0x817e, 0x41be, 0xc13e, 0x21de, 0xa15e, 0x619e,
      0xe11e, 0x11ee, 0x916e, 0x51ae, 0xd12e, 0x31ce, 0xb14e, 0x718e, 0xf10e,
      0x09f6, 0x8976, 0x49b6, 0xc936, 0x29d6, 0xa956, 0x6996, 0xe916, 0x19e6,
      0x9966, 0x59a6, 0xd926, 0x39c6, 0xb946, 0x7986, 0xf906, 0x05fa, 0x857a,
      0x45ba, 0xc53a, 0x25da, 0xa55a, 0x659a, 0xe51a, 0x15ea, 0x956a, 0x55aa,
      0xd52a, 0x35ca, 0xb54a, 0x758a, 0xf50a, 0x0df2, 0x8d72, 0x4db2, 0xcd32,
      0x2dd2, 0xad52, 0x6d92, 0xed12, 0x1de2, 0x9d62, 0x5da2, 0xdd22, 0x3dc2,
      0xbd42, 0x7d82, 0xfd02, 0x03fc, 0x837c, 0x43bc, 0xc33c, 0x23dc, 0xa35c,
      0x639c, 0xe31c, 0x13ec, 0x936c, 0x53ac, 0xd32c, 0x33cc, 0xb34c, 0x738c,
      0xf30c, 0x0bf4, 0x8b74, 0x4bb4, 0xcb34, 0x2bd4, 0xab54, 0x6b94, 0xeb14,
      0x1be4, 0x9b64, 0x5ba4, 0xdb24, 0x3bc4, 0xbb44, 0x7b84, 0xfb04, 0x07f8,
      0x8778, 0x47b8, 0xc738, 0x27d8, 0xa758, 0x6798, 0xe718, 0x17e8, 0x9768,
      0x57a8, 0xd728, 0x37c8, 0xb748, 0x7788, 0xf708, 0x0ff0, 0x8f70, 0x4fb0,
      0xcf30, 0x2fd0, 0xaf50, 0x6f90, 0xef10, 0x1fe0, 0x9f60, 0x5fa0, 0xdf20,
      0x3fc0, 0xbf40, 0x7f80, 0xff00};

  return nec_code_table[b];
}

#endif // UTIL_H

Generated using:

#include "stdio.h"


int nec_format(unsigned char b) {
  // Reverse bits as NEC sends LSB first
  b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
  b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
  b = (b & 0xAA) >> 1 | (b & 0x55) << 1;

  // Calculate inverse in lower bytes
  return (b << 8) + (~b & 0xff);
}


int main(int argc, char **argv) {
    printf("static const int nec_code_table[256] = {\n    ");
    for (unsigned int i=0; i <= 0xff; i++) {
        printf("0x%.4x", nec_format(i));

        if (i != 0xff) {
            printf(", ");
        }

        if ((i % 8 == 7)) {
            printf("\n");
            if (i != 0xff) {
              printf("    ");
            }
        }
    }
    printf("};\n");

    return 0;
}

From: https://esphome.io/components/remote_transmitter.html#remote-transmitter-transmit-nec-action

Note
In version 2021.12, the order of transferring bits was corrected from MSB to LSB in accordance with the NEC standard.
Therefore, if the configuration file has come from an earlier version of ESPhome,
it is necessary to reverse the order of the address and command bits when moving to 2021.12 or above.
For example, address: 0x84ED, command: 0x13EC becomes 0xB721 and 0x37C8 respectively.

Thus, you can now use something as simple as this:

#ifndef UTIL_H

#define UTIL_H

uint16_t nec_format(uint8_t c) {
    return (~c << 8) | c;
}

#endif

button:
  - platform: template
    name: Radiator Silvercrest Power
    id: radiator_silvercrest_power
    on_press:
      - remote_transmitter.transmit_nec:
          address: !lambda |-
            return nec_format(0x80);
          command: !lambda |-
            return nec_format(0x12);

Here's a good reading on the NEC protocol

Yeah, I fixed this last year in my own code, but forgot about this gist! thanks for the update.

What about making this the default with the upstream? is there any problem with that?

I don't understand what you are trying to say. This is a gist, you can fork and change it as you wish, and the original issue was already fixed upstream making this unnecessary as mentioned.

…

On Thu, 2 May 2024 at 14:09, Pastitas ***@***.***> wrote: @Pastitas commented on this gist. ________________________________ What about making this the default with the upstream? is there any problem with that? — Reply to this email directly, view it on GitHub or unsubscribe. You are receiving this email because you authored the thread. Triage notifications on the go with GitHub Mobile for iOS or Android.