SX127x
来自Jack's Lab
(版本间的差异)
(→Header) |
(→Header) |
||
第31行: | 第31行: | ||
可通过寄存器 RegModemConfig1 内的位 ImplicitHeaderModeOn 来控制 | 可通过寄存器 RegModemConfig1 内的位 ImplicitHeaderModeOn 来控制 | ||
− | + | ||
+ | '''Explicit Header:''' | ||
Reset 默认的模式。其能提供的信息: | Reset 默认的模式。其能提供的信息: | ||
第41行: | 第42行: | ||
The head is transmitted with maximum error correction code (4/8). It also has its own CRC to allow the receiver to discard invalid headers. | The head is transmitted with maximum error correction code (4/8). It also has its own CRC to allow the receiver to discard invalid headers. | ||
− | |||
− | + | ||
+ | '''Implicit Header:''' | ||
Header is removed from the LoRa Packet. | Header is removed from the LoRa Packet. |
2019年4月22日 (一) 13:50的版本
1 Notes
1.1 Preamble
LoRa 数据包前导码,用于接收机辩识 rx data flow。内容固定,长度可选。
默认 12 个 symbol(Bytes?), 0x8 (RegPreambleLsb) + 4
可写 RegPreambleMsb 和 RegPreambleLsb 这两个寄存器,将其改为 6 +4 ~ 65535 +4
10 symbol 的短前导码,通信够用但具有更短的接收周期。。。
当前系统一般皆适用 12 (4 + 8) 的长度:
...... ^$Get Preamble Length: state 0 ^$Preamble Length: 8 ......
1.2 Header
Explicit Header & Implicit Header
可通过寄存器 RegModemConfig1 内的位 ImplicitHeaderModeOn 来控制
Explicit Header:
Reset 默认的模式。其能提供的信息:
- Payload 长度
- The forward error correction code rate
- The presence of an optional 16-bits CRC for the payload
The head is transmitted with maximum error correction code (4/8). It also has its own CRC to allow the receiver to discard invalid headers.
Implicit Header:
Header is removed from the LoRa Packet.
Payload, Coding Rate and CRC presence are fixed.
Be advantageous to reduce transmission time