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.
All slaves should be able to send description to multicast. Receiver should be able to sort messages.
First packet can contain flags so information about acknowledge is given.

Size	Type
0x1	Package number (0: Data contains package count), overflowing
0x3	Source
0x4	Data

Header¶

Size	Type
0x4	Object
0x4	Total size
0x4	Flags
0x4	CRC32 of data

Example: CANRec¶

PC requests an complete dump from single Node. Node will just stream it out.

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.

V4¶

Single block max.262144 bytes.

Size	Decription	Examples
2	Object
2	Counter
4	Value	32Bit

The data has to be stored in memory anyways. So one block can not be infinite large.
Flash has to be written block by block. One erase sektor can be 2K. Limiting the packet size to 64K is ok for writing to flash.
Object: theoretically multiple blocks could be written at the same time. A slave could just send its whole SD-card.

Header¶

First 0x20 Bytes / 0x8 packages are the Block-Header.

Size	Type
0x2	Type; MMP1
0x1	Flags
0x1	Reserved
0x4	Total Size of this block
0x4	CRC32 of data
0x4	Header version code
0x4	Command
0x4	Address
0x4	Operation Size (e.g. erase)
0x4	-
...	Data

Commands:
- readout data
- erase application flash
- erase flash sector
- erase external flash
- erase external flash sector
- write data
- Describtion

Subaddress: e.g. flash page
Type: MMP1

Usecase¶

Write to flash¶

Data size is 0x100.
Count of blocks: 1
Number of blocks: 1