Intro¶
With the TDT-Protocol sensors can just send their values on the BUS without complex object catalogue.
An monitor-software is able to display values without knowing anything about the sensors or their configuration.
The CANId cinsists of an function code and the node id. Like CANOpen the function code is 4 Bits and the Node-ID is 7 Bit.
In CAN2.0A there can only be 128 Nodes.
CAN 2.0A: 0..0x7FF
CANOpen: 4 Bit Function code, 7 Bit Node-ID
Node-Id: 0..0x7F
Function-Code Mask: 0x780
There are 14 or 28 Filters on STM32Fs
Some STM32 have an internal 96-bit unique ID.
| Bits |
Area |
Decription |
Examples |
| 4 |
CAN-Id |
Function code |
Send object |
| 7 |
NodeId |
Sensemux WZ |
| 16 |
Data |
Object |
Set illumination |
| 8 |
Unit |
promilPwm |
| 8 |
Flags |
Confirmation required |
| 32 |
Value |
350‰ |
Function code
Function code can be 0..15 / 0x00..0x0F¶
| Code |
Decription |
Examples |
| 0x0 |
NMT-Write |
|
| 0x1 |
NMT-Send |
|
| 0x2 |
NMT-Introduce |
Device sends UID only |
| 0x3 |
NMT-setId |
Set NodeId on Device |
| 0x4 |
Alarms |
|
| 0x5 |
Write object |
Set Date, illumination |
| 0x6 |
Read object |
Get product codes |
| 0x7 |
Send object |
Send temperature |
| 0x8 |
Resend object |
Replay recorded data |
| 0x9 |
data blob |
|
IDs, ranges and commands¶
Node IDs¶
- 11-Bit-Identifier, (CAN 2.0A); 2048; 0x0 ... 0x7F0; 0x0 ... 0x7F with function code
- 29-Bit-Identifier, (CAN 2.0B); 0x20000000
| Range |
Decription |
Examples |
| 0x01-0x0F |
Network Manager |
PC |
| 0x10-0x2F |
Active controller |
CANDis |
| 0x30-0x4F |
Actor |
CANSwitch |
| 0x50-0x6F |
Sending sensors |
Sensemux, CANIO |
| 0x70-0x7F |
Passive Sensors |
CANRec |
CAN data structutre¶
| Size |
Decription |
Examples |
| 2 |
Object |
Plain Sensor value; Set illumination |
| 1 |
Unit |
hz, Float, Time, Date, Percent, promilPwm, centiCelsius, canId, room, Multipacket-String |
| 1 |
Flags |
Confirmation required |
| 4 |
Value |
32Bit |
Objects¶
| Code |
Description |
| none |
|
| ambientLight |
|
| plantLight |
|
| multimediaSwitch |
|
| mainSwitch |
|
| date |
|
| time |
|
| dummy |
|
| plantSensor |
|
| plantSensor [0-7] |
|
| firmwareVersion |
|
| firmwareDate |
|
| hardwareRevision |
|
| hardwareDate |
|
| temperatureIntern [0-7] |
|
| temperatureExtern [0-7] |
|
| humidity |
|
| VOC |
|
| Replay |
|
| Data-Dump (SD-Card) |
|
Units¶
- Date: year 2B, month 1B, day 1B
- Time: hour 1B, minute 1B, second 1B, subsecond 1B
Example: Turn on the lights¶
| Data |
Size |
Description |
| 0x300 |
29 Bits |
Function code: Write Object; All objects. |
| 0x0 |
2 Byte |
Message-Type: Global command |
| 0x1 |
1 Byte |
Data-Type: PWM Permill |
| 0x1 |
1 Byte |
Flags: None |
| 1000 |
4 Byte |
Value: Full Brightness |
Multipacket-Strings¶
There should be the posssibillity to write the complete SPI-Flash even if it takes forever.
Not every slave needs to be able to send super big blocks. But every slave should be able to
send e.g. descriptions.
There can not be multiple transfers at the same time from one node because there is no identification.
| Size |
Type |
| 0x4 |
Package number (0: Data contains package count) |
| 0x4 |
Data |
Header¶
| Size |
Type |
| 0x4 |
Total size |
| 0x4 |
Type (1=SDCard) |
| 0x4 |
Target node ID |
| 0x4 |
CRC32 of data |
Example: CANRec¶
PC requests an complete dump from single Node. Node will just stream it out.
NMT
h1. NMT
Actuator introduction¶
When introduction is requested by system command, each device must send Its UID (function code "NMT introduce") and an description.
| Size |
Decription |
Examples |
| 2 |
Object |
Object |
| 6 |
MAC/Unique ID |
48Bit |
Objects¶
| Size |
Decription |
| 1 |
Request intoruction |
| 2 |
MAC low |
| 3 |
MAC high |
| 4 |
Protocol versions |
| 5 |
Firmware version |
| 6 |
Product Code |
| 7 |
Node-Id |
Protocol versions¶
| Size |
Decription |
| 1 |
TDT Major |
| 1 |
TDT Minor |
| 1 |
NMT Major |
| 1 |
NMT Minor |
| 1 |
Blob Major |
| 1 |
Blob Minor |
Usecase: Setting Node-ID¶
Two nodes may have the same Node-ID. When scanning the network, the nodes will overwrite the counterparts information.
The "NMT-Introduce"-function code is used by the nodes to send theyr complete UID. NMT can then send
The new NodeID can not be part of the CAN-ID because the device may be filtering it out. (The whole NMT )
| Size |
Decription |
Examples |
| 1 |
Packet type |
Standard TDT packet |
| 1 |
Sub-Id; |
Futher index; Sub-Sensor or more specifi kind of thing to be set |
| 1 |
Data type |
Int, Float, Time, Date, Percent, Promil, Multipacket-String |
| 1 |
Unit |
Hz, °C, Time, Date, PWM, CAN-ID, Name, Description, Room |
| 4 |
Value |
32Bit |
| Size |
Decription |
Examples |
| 2 |
Object |
|
| 1 |
Sub-Id; |
Flags, Subid |
| 1 |
Unit/Type |
Hz_int, °C_centi, Time, Date, PWM_milli, CAN-ID, Name, Description, Room |
| 4 |
Value |
32Bit |
Flags¶
4 Bit multi message count
4 Bit multi message pos
Length in Bytes given via CAN?
Strings with max. 64 characters.
Multimessage package¶
There should be the possibillity to write the complete SPI-Flash even if it takes forever.
Not every slave needs to be able to send super big blocks. But every slave should be able to
send e.g. descriptions.
Alarms/Alerts¶
Devices should indicate issues; e.g.:
Object structutre¶
| Size |
Decription |
Examples |
| 2 |
Object |
I2C, VBat, |
| 1 |
Unit |
hz, Float, Time, Date, Percent, promilPwm, centiCelsius, canId, room, Multipacket-String |
| 1 |
Issue |
Whats wrong, Undervolts, Communication error |
| 4 |
Value |
32Bit |