Plain C library for parsing AT commands for use in host devices.
- blazing fast, non-blocking, robust implementation
- 100% static implementation (without any dynamic memory allocation)
- very small footprint (both RAM and ROM)
- support for READ, WRITE, TEST and RUN type commands
- commands shortcuts (auto select best command candidate)
- single request - multiple responses
- unsolicited read/test command support
- hold state for delayed responses for time-consuming tasks
- high-level memory variables mapping arguments parsing
- variables accessors (read and write, read only, write only)
- automatic arguments types validating
- automatic format test responses for commands with variables
- CRLF and LF compatible
- case-insensitive
- dedicated for embedded systems
- object-oriented architecture
- separated interface for low-level layer
- fully asynchronous input/output operations
- multiplatform and portable
- asynchronous api with event callbacks
- print registered commands list feature
- only two source files
- wide unit tests
Build and install:
cmake .
make
make test
sudo make installAT+PRINT=? # TEST command
+PRINT=<X:UINT8[RW]>,<Y:UINT8[RW]>,<MESSAGE:STRING[RW]> # Automatic response
Printing something special at (X,Y). # Automatic response
OK # Automatic acknowledge
AT+PRINT? # READ command
+PRINT=0,0,"" # Automatic response
OK # Automatic acknowledge
AT+PRINT=xyz,-2 # WRITE command
ERROR # Automatic acknowledge
AT+PRINT=1,2,"test" # WRITE command
OK # Automatic acknowledge
AT+PRINT # RUN command
some printing at (1,2) with text "test" # Manual response
OK # Automatic acknowledgeAT+START=? # TEST command
+START=<MODE:UINT32[WO]> # Automatic response
Start scanning after write (0 - wifi, 1 - bluetooth). # Automatic response
OK # Automatic acknowledge
AT+START=0 # WRITE command
+SCAN=-10,"wifi1" # Unsolicited read response
+SCAN=-50,"wifi2" # Unsolicited read response
+SCAN=-20,"wifi3" # Unsolicited read response
OK # Unsolicited acknowledge
AT+START=1 # WRITE command
+SCAN=-20,"bluetooth1" # Unsolicited read response
OK # Unsolicited acknowledge
AT+SCAN=? # TEST command
+SCAN=<RSSI:INT32[RO]>,<SSID:STRING[RO]> # Automatic response
Scan result record. # Automatic response
OK # Automatic acknowledgeDefine High-Level variables:
static uint8_t x;
static uint8_t y;
static char msg[32];
static struct cat_variable go_vars[] = {
{
.type = CAT_VAR_UINT_DEC, /* unsigned int variable */
.data = &x,
.data_size = sizeof(x),
.write = x_write,
.name = "X",
.access = CAT_VAR_ACCESS_READ_WRITE,
},
{
.type = CAT_VAR_UINT_DEC, /* unsigned int variable */
.data = &y,
.data_size = sizeof(y),
.write = y_write,
.access = CAT_VAR_ACCESS_READ_WRITE,
},
{
.type = CAT_VAR_BUF_STRING, /* string variable */
.data = msg,
.data_size = sizeof(msg),
.write = msg_write,
.access = CAT_VAR_ACCESS_READ_WRITE,
}
};Define AT commands descriptor:
static struct cat_command cmds[] = {
{
.name = "TEST",
.read = test_read, /* read handler for ATTEST? command */
.write = test_write, /* write handler for ATTEST={val} command */
.run = test_run /* run handler for ATTEST command */
},
{
.name = "+NUM",
.write = num_write, /* write handler for AT+NUM={val} command */
.read = num_read /* read handler for AT+NUM? command */
},
{
.name = "+GO",
.write = go_write, /* write handler for AT+GO={x},{y},{msg} command */
.var = go_vars, /* attach variables to command */
.var_num = sizeof(go_vars) / sizeof(go_vars[0]),
.need_all_vars = true
},
{
.name = "RESTART",
.run = restart_run /* run handler for ATRESTART command */
}
};Define AT command parser descriptor:
static char working_buf[128]; /* working buffer, must be declared manually */
static struct cat_command_group cmd_group = {
.cmd = cmds,
.cmd_num = sizeof(cmds) / sizeof(cmds[0]),
};
static struct cat_command_group *cmd_desc[] = {
&cmd_group
};
static struct cat_descriptor desc = {
.cmd_group = cmd_desc,
.cmd_group_num = sizeof(cmd_desc) / sizeof(cmd_desc[0]),
.buf = working_buf,
.buf_size = sizeof(working_buf),
};Define IO low-level layer interface:
static int write_char(char ch)
{
putc(ch, stdout);
return 1;
}
static int read_char(char *ch)
{
*ch = getch();
return 1;
}
static struct cat_io_interface iface = {
.read = read_char,
.write = write_char
};Initialize AT command parser and run:
struct cat_object at; /* at command parser object */
cat_init(&at, &desc, &iface, NULL); /* initialize at command parser object */
while (1) {
cat_service(&at) /* periodically call at command parser service */
... /* other stuff, running in main loop */
}