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	Decription	Examples
4	Function code	Send object
7	NodeId	Sensemux WZ

Function code¶

Code	Decription	Examples
0x0	NMT-Write
0x1	NMT-Send
0x2	Alarms
0x3	Write object	Set Date, illumination
0x4	Read object	Get product codes
0x5	Send object	Send temperature
0x6	Resend object	Replay recorded data
0x7	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

Object 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	-	Reserved
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: Permill
0x1	1 Byte	PWM: PWM permilli
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¶

Actuator introduction¶

When introduction is requested by system command, each device must send 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

V2¶

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

V3¶

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.:

• Battery low
• I2C problems

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