Trying to standardize the way I access sensors.
Part | In Checksum | Type | Description |
---|---|---|---|
Header | uint8_t[2] |
default $K |
|
Size | x | uint16_t |
0-65,535 bytes, stored as [L,H] => `(H << 8) |
Type | x | uint8_t |
255 message IDs, 0 is not allowed as an ID |
Data | x | uint8_t[Size] |
payload data array |
Checksum | uint8_t |
XOR of size, type, and data bytes |
0 | 1 | 2 | 3 | 4 | ... | -1 |
---|---|---|---|---|---|---|
$ |
K |
L | H | T | ... | checksum |
Type | Bytes | Format | Python | C/C++ |
---|---|---|---|---|
uint8 |
1 | B |
int |
uint8_t |
uint16 |
2 | H |
int |
uint16_t |
uint32 |
4 | I |
int |
uint32_t |
uint64 |
8 | Q |
int |
uint64_t |
int8 |
1 | b |
int |
int8_t |
int16 |
2 | h |
int |
int16_t |
int32 |
4 | i |
int |
int32_t |
int64 |
8 | q |
int |
int64_t |
float |
4 | f |
float |
float |
double |
8 | d |
float |
double |
- Make C and python functions/objects match ... they are different right now
- Should I move to a real CRC-8 checksum?
- Remove messages from library. This is just a binary packer and
not dependant on the message format other than, it is a
struct
- c++: Make a header only library
- Generate C and Python messages from a template instead of writing independently
- c++: rename
YivoPack_t
to something else likeyivopkt_t
- Add method
bool has_valid_chksum()
? Class could calculate checksum and then compare to its checksum
- Add method
- c++: Should I move away from
std::vector
and to a fixed array size, since on create of a message, I know the complete size ... it isn't a mystery at that point- would now have to use
new
anddelete
which aren't my favorite
- would now have to use
from yivo import Yivo, MsgInfo
# make some messages we want to send/receive
A = namedtuple("A","x y") # id = 1
B = namedtuple("B", "x y z t") # id = 2
msgdb = MsgInfo()
msgdb[1] = ("2f", A) # 2 floats
msgdb[2] = ("4f", B) # 4 floats
yivo = Yivo(msgdb)
pkt = yivo.pack(1, A(1.,2.))
id = 0
while id == 0:
b = serial_read() # get a byte from somewhere
id = yivo.parse(b) # 0 or msg_id
err, msg = yivo.unpack() # err > 0 if failure to unpack
yivopkt_t
: packs/unpacks (or encodes/decodes) cstructs
for transmissionuint8_t* data()
: get point to bufferuint16_t size()
: get size of bufferuint8_t msg_id()
: get message idvoid pack(id,*data,size)
: encode astruct
to binaryT unpack<T>()
: decode a binary message to astruct
Yivo
: basically a state machine for reading in serial data and determining when you have a message to readuint8_t parse(c)
: read in a byte at a time and return an ID or 0void get_packet(pkt)
: copy binary message toyivopkt_t
#include <yivo.hpp>
// some messages
struct A {int a;}; // id 1
struct B {int b;}; // id 2
Yivo yivo;
yivopkt_t pkt;
pkt.pack(1, A{1}, sizeof(A));
serial_send(pkt.data(), pkt.size()); // somehow send a message
uint8_t id = 0;
while (id == 0) {
uint8_t b = serial_read(); // get a byte from somewhere
id = yivo.parse(b);
}
yivopkt_t rep;
yivo.get_packet(rep);
// then decode the received message
if (id == 1) A a = rep.unpack<A>();
else if (id == 2) B b = rep.unpack<B>();
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