Distributed System Interface
DSI3
DSI3 是第三代卫星接口总线，主要用于中央主接口与多个卫星节点之间的安全关键通信（一主多从）
从节点
- 简单状态机
- 微处理器
- DSP控制器
- raw / preprocessed data sources
- single / multiple data sources
- output / control 功能
Discovery Mode
- 识别slave位置
- 分配unique 物理地址
fail silent philosophy
Background Diagnostic Mode
- 诊断
- 功能安全
主要目标应用领域是汽车安全气囊系统，但预计新功能允许用在其他的领域
基本特性
- Bandwidth Improvements
- t Time-Division-Multiple-Access (TDMA)
- EMC Improvements
- Data Integrity Improvements
- Cost Controls
总线拓扑，功能
point-to-point
daisy-chain
parallel
Signal Function Class
- 周期性数据采集
Power Function Class
- 功率输出
Signal：Command and Response
Signal：Periodic Data Collection Mode
Signal：Background Diagnostic Mode
Power：Background Diagnostic Mode
物理层编码
Forward Channel Data Bit Encoding - Master Perspective
Reverse Communication Channel Data Bit Encoding
一个symbol <–> 3个chip <–> 12byte
三种电流有27种组合，但是0开始(和Iq一样)去掉，去掉全相同的两个，即剩下16个，对应4byte
Multi-Level Source Coded TDMA Response Frame
Link Layer
Signal Function Class
Command and Response Mode Packet Formats
Command and Response Mode - Command Format
| Physical Address | Command | Extended Data | Register Data | CRC |
|---|---|---|---|---|
| MSB | LSB | |||
| PA[3:0] | CMD[3:0] | ED[7:0] | RD[7:0] | CRC[7:0] |
Command and Response Mode - Response Format
| Physical Address | Status | Extended Data | Register Data | CRC |
|---|---|---|---|---|
| MSB | LSB | |||
| PA[3:0] | S[3:0] | ED[7:0] | RD[7:0] | CRC[7:0] |
Command and Response Mode - Field Definitions
| Field | Command Packet | Length (Bits) | Field | Response Packet | Length (Bits) |
|---|---|---|---|---|---|
| PA[3:0] | Physical Address | 4 | PA[3:0] | Physical Address | 4 |
| CMD[3:0] | Command | 4 | S[3:0] | Status | 4 |
| ED[7:0] | Extended Data | 8 | ED[7:0] | Extended Data | 8 |
| RD[7:0] | Register Data | 8 | RD[7:0] | Register Data | 8 |
| CRC[7:0] | 8 | CRC[7:0] | 8 |
Command and Response Mode - Supported Commands
| Command | Command Description | Extended Data ED[7:0] |
|---|---|---|
| 0 | Register Read | Register Address RA[7:0] |
| 2 – 7 | Device / System Specific | Device / System Specific |
| 8 | Register Write | Register Address RA[7:0] |
| 9 - 15 | Device / System Specific | Device / System Specific |
Command and Response Mode - Status Definitions
Periodic Data Collection Mode Packet Formats
Background Diagnostic Mode Packet Formats
Power Function Class Transactions
基本和Command and Response Mode Packet Formats的命令一致
slave address
- DSI3 使用 物理地址 + 可选源标识地址（source identification addresses）
- 每个物理从机必须有唯一 4-bit 物理地址
- 地址 0 为 全局地址（global address），用于全局命令，无需响应
| PA3 | PA2 | PA1 | PA0 | Slave Number |
|---|---|---|---|---|
| 0 | 0 | 0 | 0 | All Slaves |
| 0 | 0 | 1 | 0 | Slave 2 |
| 0 | 0 | 1 | 1 | Slave 3 |
| 0 | 1 | 0 | 0 | Slave 4 |
| 0 | 1 | 0 | 1 | Slave 5 |
| 0 | 1 | 1 | 0 | Slave 6 |
| 0 | 1 | 1 | 1 | Slave 7 |
| 1 | 0 | 0 | 0 | Slave 8 |
| 1 | 0 | 0 | 1 | Slave 9 |
| 1 | 0 | 1 | 0 | Slave 10 |
| 1 | 0 | 1 | 1 | Slave 11 |
| 1 | 1 | 0 | 0 | Slave 12 |
| 1 | 1 | 0 | 1 | Slave 13 |
| 1 | 1 | 1 | 0 | Slave 14 |
| 1 | 1 | 1 | 1 | Slave 15 |
自动分配地址
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