From 71f320638ea59dce4d8dcc8a707912a19005afe2 Mon Sep 17 00:00:00 2001 From: Michael Kaiser Date: Sat, 25 Nov 2017 21:14:12 +0100 Subject: [PATCH] Fix protocol description (#125) * Fix discovery packet format description * fix MAC address offset * Command packet format description * Data description --- protocol.md | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/protocol.md b/protocol.md index e9ac99b13..2e388d749 100644 --- a/protocol.md +++ b/protocol.md @@ -40,13 +40,14 @@ To discover Broadlink devices on the local network, send a 48 byte packet with t |0x00-0x07|00| |0x08-0x0b|Current offset from GMT as a little-endian 32 bit integer| |0x0c-0x0d|Current year as a little-endian 16 bit integer| -|0x0e|Current number of minutes past the hour| -|0x0f|Current number of hours past midnight| -|0x10|Current number of years past the century| -|0x11|Current day of the week (Monday = 0, Tuesday = 1, etc)| +|0x0e|Current number of seconds past the minute| +|0x0f|Current number of minutes past the hour| +|0x10|Current number of hours past midnight| +|0x11|Current day of the week (Monday = 1, Tuesday = 2, etc)| |0x12|Current day in month| |0x13|Current month| -|0x19-0x1b|Local IP address| +|0x14-0x17|00| +|0x18-0x1b|Local IP address| |0x1c-0x1d|Source port as a little-endian 16 bit integer| |0x1e-0x1f|00| |0x20-0x21|Checksum as a little-endian 16 bit integer| @@ -61,7 +62,7 @@ Response (any unicast response): | Offset | Contents | |---------|----------| |0x34-0x35|Device type as a little-endian 16 bit integer (see device type mapping)| -|0x3a-0x40|MAC address of the target device| +|0x3a-0x3f|MAC address of the target device| Device type mapping: @@ -107,20 +108,19 @@ The command packet header is 56 bytes long with the following format: |0x08-0x1f|00| |0x20-0x21|Checksum of full packet as a little-endian 16 bit integer| |0x22-0x23|00| -|0x24|0x2a| -|0x25|0x27| +|0x24-0x25|Device type as a little-endian 16 bit integer| |0x26-0x27|Command code as a little-endian 16 bit integer| |0x28-0x29|Packet count as a little-endian 16 bit integer| |0x2a-0x2f|Local MAC address| |0x30-0x33|Local device ID (obtained during authentication, 00 before authentication)| -|0x34-0x35|Checksum of packet header as a little-endian 16 bit integer +|0x34-0x35|Checksum of unencrypted payload as a little-endian 16 bit integer |0x36-0x37|00| -The payload is appended immediately after this. The checksum at 0x34 is calculated *before* the payload is appended, and covers only the header. The checksum at 0x20 is calculated *after* the payload is appended, and covers the entire packet (including the checksum at 0x34). Therefore: +The payload is appended immediately after this. The checksum at 0x20 is calculated *after* the payload is appended, and covers the entire packet (including the checksum at 0x34). Therefore: 1. Generate packet header with checksum values set to 0 -2. Set the checksum initialisation value to 0xbeaf and calculate the checksum of the packet header. Set 0x34-0x35 to this value. -3. Append the payload +2. Set the checksum initialisation value to 0xbeaf and calculate the checksum of the unencrypted payload. Set 0x34-0x35 to this value. +3. Encrypt and append the payload 4. Set the checksum initialisation value to 0xbeaf and calculate the checksum of the entire packet. Set 0x20-0x21 to this value. Authorisation @@ -180,7 +180,7 @@ Send the following payload with a command byte of 0x006a |0x04|0x26 = IR, 0xb2 for RF 433Mhz, 0xd7 for RF 315Mhz| |0x05|repeat count, (0 = no repeat, 1 send twice, .....)| |0x06-0x07|Length of the following data in little endian| -|0x08 ....|Pulse lengths in 32,84ms units (ms * 269 / 8192 works very well)| +|0x08 ....|Pulse lengths in 2^-15 s units (µs * 269 / 8192 works very well)| |....|0x0d 0x05 at the end for IR only| Each value is represented by one byte. If the length exceeds one byte