CAS50 data types¶
Data in the CAS50 protocol is composed a header, followed by data parts,
all prefixed with 0x3A.
Headers are always 50 bytes long, and of the following format:
Offset |
Size |
Field name |
Description |
Values |
|---|---|---|---|---|
0 (0x00) |
1 B |
Prefix |
Header prefix. |
|
1 (0x01) |
4 B |
Format (FMT) |
Format of the following data packets. |
|
5 (0x05) |
44 B |
Format-specific data |
See the type description for the format of this component.
If the type-specific data is less than 44 bytes, the rest is filled
with |
|
49 (0x31) |
1 B |
Checksum (CS) |
|
The type-specific data, and count, size and format of data packets sent after the header depend on the format (FMT).
See the following subsections for more information.
END\xFF End¶
This header represents an end of sequence. It is only used with the CASIOLINK protocol, when using the CAS50 header format.
This is not followed by any data parts.
FNC\0 Function¶
Todo
Describe this.
IMG\0 Image¶
Todo
Describe this more.
MEM\0 Memory Dump¶
Such packets carry over a memory dump.
Format-specific data for this format is the following:
Offset |
Size |
Field name |
Description |
Values |
|---|---|---|---|---|
0 (0x00) |
2 B |
Data Type (DT) |
Data type, presenting the nature of the data depending on the format. |
|
2 (0x02) |
4 B |
Size (S) |
Size of the data accompanying the header. |
Big endian 16-bit unsigned integer. |
Known data types for this format are:
Data Type (DT) |
Description |
|---|---|
|
Backup. |
Todo
Describe this more. Notably, there is more to the header!
REQ\0 Request¶
Todo
Describe this.
TXT\0 Textual File¶
Such packets carry over a main memory textual file.
Format-specific data for this format is the following:
Offset |
Size |
Field name |
Description |
Values |
|---|---|---|---|---|
0 (0x00) |
2 B |
Data Type (DT) |
Data type, presenting the nature of the data depending on the format. |
|
2 (0x02) |
4 B |
Size (S) |
Size of the data accompanying the header (big endian). For most data, this is either set to 0 if there are no data part, or the size of the data part plus 2 otherwise. However, some types override this behaviour to use it elsewhere. |
|
6 (0x06) |
8 B |
File Name (FN) |
Name of the file, with unset bytes being set to |
|
14 (0x0E) |
8 B |
Reserved |
Set to |
|
22 (0x16) |
8 B |
File Password (FP) |
Password of the file, with unset bytes being set to |
|
30 (0x1E) |
2 B |
Option 1. |
|
|
32 (0x20) |
2 B |
Option 2 |
Set to |
|
34 (0x22) |
2 B |
Option 3 |
Set to |
|
36 (0x24) |
2 B |
Option 4 |
Set to |
Known data types for this format are the following:
Data Type (DT) |
Description |
|---|---|
|
Program. |
VAL\0 Value¶
Such packets carry over one or more values.
Format-specific data for this format is the following:
Offset |
Size |
Field name |
Description |
Values |
|---|---|---|---|---|
0 (0x00) |
2 B |
Data Type (DT) |
Data type, presenting the nature of the data depending on the format. |
|
2 (0x02) |
2 B |
Height (H) |
Big endian 16-bit unsigned integer. |
|
4 (0x04) |
2 B |
Width (W) |
Width of the array. Set to 0 for lists (i.e. only width is used). |
Big endian 16-bit unsigned integer. |
6 (0x06) |
8 B |
Reserved |
Set to |
|
14 (0x0E) |
8 B |
Unknown |
|
Known data types for this format are the following:
Data Type (DT) |
Description |
|---|---|
|
Matrix |
|
List |
Every data payload represents a value in the collection, using a 14-byte format composed of the following:
Offset |
Size |
Field name |
Description |
Values |
|---|---|---|---|---|
0 (0x00) |
2 B |
Y coordinate (Y) |
Big endian 16-bit unsigned integer. |
|
2 (0x02) |
2 B |
X coordinate (X) |
Big endian 16-bit unsigned integer. |
|
4 (0x04) |
10 B |
Value (V) |
Todo
Check the format and its order!