eInstruction CPS-IR

8-button infrared remotes with unique serial numbers.

ir remote

1. Framing

scope measurements, in microseconds:

  • start: 976

  • pause: 524

  • pulse: 160

  • zero: 472

  • one: 952

Circuit has a 455 kHz oscillator. 2.20 us period.

  • LED ON time is 3 clocks.

  • LEF OFF time is 9 clocks.

  • Period tick is 12 clocks / 26.37 us / 37.917 kHz.

  • start burst is 38 pulses. 1002.2 us or ON-ON of 995.6 us.

  • short burst is 7 LED pulses. 184us period, but ON-ON width is 178 us.

  • zero gap is 476 us from start of last to start of next LED pulse. 18 ticks, so gap is 17 ticks.

  • one gap is 950 us from start of last to start of next LED pulse. 36 ticks, gap is 35 ticks.

2. Sample decodes

2.1. Serial 10679c

prefix

0001 0000 0110 0111 1001 1100 0x10679c
A

0110 0011 0x10679c63
B

0111 0010 0x10679c72
C

1010 1111 0x10679caf
D

1110 1011 0x10679ceb
E

1011 1110 0x10679cbe
F

1111 1010 0x10679cfa
G

1001 1100 0x10679c9c
H

1101 1000 0x10679cd8

2.2. Serial 1051b5

prefix

0001 0000 0101 0001 1011 0101 0x1051b5
A

1000 0011 0x1051b583
B

1001 0010 0x1051b592
C

0100 1111 0x1051b54f
D

0000 1011 0x1051b50b
E

0101 1110 0x1051b55e
F

0001 1010 0x1051b51a
G

0111 1100 0x1051b57c
H

0011 1000 0x1051b538

3. Encoding scheme

Bits are in time-order. Leftmost bit is the first received from the packet.

iiii iiii iiii iiii iiii iiii xxxx kkkk (32 bits)

octets

id[2], id[1], id[0], b

b octet

xxxx kkkk
upper 4-bits of last byte have unknown meaning.

keymap 0x0f & key

  • 0x03 → A

  • 0x02 → B

  • 0x0f → C

  • 0x0b → D

  • 0x0e → E

  • 0x0a → F or *

  • 0x0c → G or <

  • 0x08 → H or >