SCPI parser and status register model implementation (device side) written in C
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scpi_parser/README.md

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9 years ago
# SCPI parser
This library provides a simple ("KISS") SCPI implementation for embedded devices (instruments).
The implementation is not 100% complete, but it's sufficient for basic SCPI communication.
## What's supported
- The hierarchical header model (commands with colon)
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- Long and short header variants (eg. `SYSTem?`)
- Easy configuration with one const array of structs and callback functions (see `main.c`)
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- Semicolon for chaining commands on the same level
- String, Int, Float, Bool arguments
- Block data argument with callback each N received bytes (configurable)
- Status Register model
- Error queue including error messages from the SCPI spec
- All mandatory SCPI commands (headers) are implemented as built-ins
Built-in commands can be overriden in user command array.
## How to use
To test it with regular gcc, run the Makefile in the `example` directory.
The main Makefile builds a library for ARM Cortex M4 (can be easily adjusted for others).
### Stubs to implement
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Here's an overview of stubs you have to implement (at the time of writing this readme):
```c
#include "scpi_parser.h"
// Receive byte - call:
// scpi_handle_byte()
// scpi_handle_string()
// ---- DEVICE IMPLEMENTATION ----
const SCPI_error_desc scpi_user_errors[] = {
{10, "Custom error"}, // add your custom errors here (positive numbers)
{/*END*/} // <-- end marker
};
void scpi_send_byte_impl(uint8_t b)
{
// send the byte to master (over UART?)
}
const char *scpi_device_identifier(void)
{
// fill in your device info
// possible to eg. read a serial # from EEPROM
return "<manufacturer>,<product>,<serial#>,<version>";
}
/* Custom commands */
const SCPI_command_t scpi_commands[] = {
// see the struct definition for more details. Examples:
{
.levels = {"APPLy", "SINe"},
.params = {SCPI_DT_INT, SCPI_DT_FLOAT, SCPI_DT_FLOAT},
.callback = cmd_APPL_SIN_cb
},
{
.levels = {"DATA", "BLOB"},
.params = {SCPI_DT_BLOB},
.callback = cmd_DATA_BLOB_cb, // <-- command callback
.blob_chunk = 4,
.blob_callback = cmd_DATA_BLOB_data // <-- data callback
},
{/*END*/} // <-- important! Marks end of the array
};
// ---- OPTIONAL CALLBACKS ----
void scpi_service_request_impl(void)
{
// Called when the SRQ flag in Status Byte is set.
// Device should somehow send the request to master.
}
// Device specific implementation of common commands
// (status registers etc are handled internally)
void scpi_user_CLS(void) { /*...*/ }
void scpi_user_RST(void) { /*...*/ }
void scpi_user_TSTq(void) { /*...*/ }
```
See the header files for more info.
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## What is missing
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- Number units and metric suffixes (k,M,G,m,u,n)
- DEF, MIN, MAX, INF, NINF argument values for numbers
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Support for units and "constants" (DEF etc) in numeric fields will need some larger changes to the numeric parser and `SCPI_argval_t`.
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Feel free to propose a pull request implementing any missing features.