You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
111 lines
2.8 KiB
111 lines
2.8 KiB
9 years ago
|
SBMP library, v1.3
|
||
|
|
==================
|
||
|
|
|
||
|
|
This is a reference implementation of SBMP, which should be usable in embedded
|
||
|
|
environment.
|
||
|
|
|
||
|
|
The library cosists of a **Framing layer**, **Datagram middleware** and a **Session layer**.
|
||
|
|
|
||
|
|
How to use
|
||
|
|
----------
|
||
|
|
|
||
|
|
The framing layer is isolated in the `sbmp_frame` module, and can be used on it's own,
|
||
|
|
if sessions are not needed. That gives you reliable data transfer with error detection.
|
||
|
|
|
||
|
|
If you want to *get the most out of SBMP*, use the session layer. Session layer functions are
|
||
|
|
namespaced `sbmp_ep_` ("ep" stands for endpoint).
|
||
|
|
|
||
|
|
All header files are included in `sbmp.h`, which is the only file you should
|
||
|
|
`#include` in your application.
|
||
|
|
|
||
|
|
Read comments in the examples to see how to use the library.
|
||
|
|
|
||
|
|
Configuration & porting
|
||
|
|
-----------------------
|
||
|
|
|
||
|
|
You can customize a lot of aspects of SBMP in `sbmp_config.h`.
|
||
|
|
|
||
|
|
If you included the library as a submodule, and want to avoid manual edits, you can set
|
||
|
|
the options using compiler flags (eg. to disable CRC32: `-DSBMP_HAS_CRC32=0`).
|
||
|
|
|
||
|
|
**What to change for Arduino**
|
||
|
|
|
||
|
|
Basically disable all you can in the config file.
|
||
|
|
|
||
|
|
- You don't want `malloc()`
|
||
|
|
- Logging is useless if there's only one USART anyway
|
||
|
|
- CRC32 can be replaced with XOR if you don't care about reliability that much.
|
||
|
|
|
||
|
|
This gains you a huge size reduction, and the whole library will take only around
|
||
|
|
2.5 kB flash and 150 B ram (of course, not including your Rx buffer).
|
||
|
|
|
||
|
|
It works really well for ATmega328P - the usual Arduino chip.
|
||
|
|
|
||
|
|
Example for AVR
|
||
|
|
---------------
|
||
|
|
|
||
|
|
This example uses the [AVR C boilerplate](https://github.com/MightyPork/avr-c-boilerplate).
|
||
|
|
|
||
|
|
It's here just to show how to set up SBMP in your AVR application.
|
||
|
|
|
||
|
|
**NOTE:** This example uses static allocation of the struct and buffer.
|
||
|
|
|
||
|
|
If you pass NULLs to the init function, it will `malloc()` it for you
|
||
|
|
and return a pointer to the Endpoint.
|
||
|
|
|
||
|
|
```c
|
||
|
|
#include <avr/io.h> // register definitions
|
||
|
|
#include <avr/interrupt.h> // interrupt vectors
|
||
|
|
|
||
|
|
#include <stdint.h>
|
||
|
|
#include <stdbool.h>
|
||
|
|
|
||
|
|
// AVR C boilerplate libs
|
||
|
|
#include "lib/iopins.h"
|
||
|
|
#include "lib/usart.h"
|
||
|
|
|
||
|
|
// SBMP
|
||
|
|
#include "sbmp/sbmp.h"
|
||
|
|
|
||
|
|
// SBMP globals
|
||
|
|
#define RXBUF_LEN 128
|
||
|
|
static uint8_t rxbuf[RXBUF_LEN];
|
||
|
|
static SBMP_Endpoint ep;
|
||
|
|
|
||
|
|
/** USART receive handler */
|
||
|
|
ISR(USART_RX_vect)
|
||
|
|
{
|
||
|
|
// Get the byte and pass it to SBMP
|
||
|
|
uint8_t b = usart_rx();
|
||
|
|
sbmp_ep_receive(&ep, b); // WARN: This can fail. Should check retval.
|
||
|
|
}
|
||
|
|
|
||
|
|
/** Message received from SBMP */
|
||
|
|
void message_received(SBMP_Datagram *dg)
|
||
|
|
{
|
||
|
|
// ...
|
||
|
|
}
|
||
|
|
|
||
|
|
int main()
|
||
|
|
{
|
||
|
|
usart_init(BAUD_115200);
|
||
|
|
usart_isr_rx_enable(true); // enable the interrupt
|
||
|
|
|
||
|
|
// init SBMP
|
||
|
|
sbmp_ep_init(&ep, rxbuf, RXBUF_LEN, message_received, usart_tx);
|
||
|
|
|
||
|
|
// ...additional SBMP configuration if needed...
|
||
|
|
|
||
|
|
// enable rx, tx
|
||
|
|
sbmp_ep_enable(&ep, true);
|
||
|
|
|
||
|
|
// globally enable interrupts (for the USART_RX handler)
|
||
|
|
sei();
|
||
|
|
|
||
|
|
while (1) {
|
||
|
|
// ... do stuff
|
||
|
|
}
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|