目 录
1.0 Introduction ................................................................................................. 4
2.0 General description ....................................................................................... 4
2.1 Bus and protocol definitions .................................................................. 4
2.2 General characteristics of slaves ............................................................. 5
3.0 Message formats ............................................................................................ 6
3.1 General .................................................................................................. 6
3.2 Start and stop characters ........................................................................ 7
3.3 Header content ...................................................................................... 8
3.4 Data part contents ................................................................................. 9
3.5 Checksum and parity bit ....................................................................... 9
4.0 Message types and use ................................................................................. 10
4.1 Overview of master and slave messages ................................................ 10
4.2 Communications between master and slaves ....................................... 10
4.2.1 Data read from slave .................................................................. 11
4.2.2 Data write to slave ..................................................................... 11
4.3 Contents of different types of messages ............................................... 12
4.3.1 Message type R (Read) .............................................................. 12
4.3.2 Message type D (Data) .............................................................. 12
4.3.3 Message type W (Write) ............................................................ 12
4.3.4 Message type A (Ack) ................................................................ 12
4.3.5 Message type N (Nack).............................................................. 13
4.4 Clock message ..................................................................................... 14
5.0 Data transfer in messages ............................................................................ 15
5.1 Data categories .................................................................................... 15
5.2 Data belonging to different data categories .......................................... 15
5.2.1 Data categories I, O, S, V, and M .............................................. 15
5.2.2 Data categories F, T, D and C .................................................... 17
5.2.3 Data categories L and B ............................................................. 18
5.2.4 Data category A ......................................................................... 20
6.0 Delay durations .......................................................................................... 20
附录:
1. 保留的 SPA-bus 数据条目
2. SPA-bus 推荐硬件.
3. Implementation limitations.
4. 扩充: String transfer with exrended character set
5. SPA 文件传输
2