Fine error reporting can now be disabled to save program space, added callback for new error, changed some callback names.

Makefile

@@ -33,6 +33,9 @@ CFLAGS      += -Wredundant-decls -Wfloat-equal -Wsign-compare
 CFLAGS      += -fno-common -ffunction-sections -fdata-sections -Wunused-function
 CFLAGS      += -I$(INCL_DIR)
 
+CFLAGS += -DSCPI_FINE_ERRORS
+CFLAGS += -DSCPI_WEIRD_ERRORS
+
 ###############################################################################
 
 all: lib

example/Makefile

@@ -11,10 +11,12 @@ CFLAGS      += -Wall -Wextra -Wshadow
 CFLAGS      += -Wwrite-strings -Wold-style-definition -Winline
 CFLAGS      += -Wredundant-decls -Wfloat-equal -Wsign-compare -Wunused-function
 
+CFLAGS += -DSCPI_FINE_ERRORS
+
 CC = gcc
 
 %.o: %.c
-	
+
 
 all: example.elf
 

example/example.c

@@ -30,10 +30,12 @@ int main(void)
 	send_cmd("SYST:ERR:COUNT?\n");
 	send_cmd("SYST:ERR:NEXT?\n");
 
+	send_cmd("ERROR_FALLBACK\n"); // test fallback to closest related error
+
 	// test chardata
 	send_cmd("CHARD FOOBAR123_MOO_abcdef_HELLO, 12\n");
-	
-	
+
+
 	send_cmd("SYST:ERR:ALL?\n");
 }
 
@@ -56,20 +58,25 @@ void scpi_send_byte_impl(uint8_t b)
 }
 
 
-const char *scpi_device_identifier(void)
+const char *scpi_user_IDN(void)
+{
+	return "MightyPork,Test SCPI device,0,0.1";
+}
+
+
+/** Error callback */
+void scpi_user_error(int16_t errno, const char * msg)
 {
-	return "FEL CVUT,DDS1,0,0.1";
+	printf("### ERROR ADDED: %d, %s ###\n", errno, msg);
 }
 
 
-void scpi_service_request_impl(void)
+/** Service request impl */
+void scpi_user_SRQ(void)
 {
 	// NOTE: Actual instrument should send SRQ event somehow
 
-	printf("[SRQ] - error: ");
-	char buf[256];
-	scpi_read_error_noremove(buf); // show error message (for debug)
-	printf("%s\n", buf);
+	printf("[Service Request]\n");
 }
 
 
@@ -115,6 +122,16 @@ void cmd_CHARD_cb(const SCPI_argval_t *args)
 }
 
 
+void cmd_ERROR_FALLBACK_cb(const SCPI_argval_t *args)
+{
+	(void) args;
+
+	printf("Testing the error fallback feature...\n");
+
+	scpi_add_error(-427, NULL);
+}
+
+
 // Command definition (mandatory commands are built-in)
 const SCPI_command_t scpi_commands[] = {
 	{
@@ -138,6 +155,10 @@ const SCPI_command_t scpi_commands[] = {
 		.levels = {"USeRERRor"},
 		.callback = cmd_USRERR_cb
 	},
+	{
+		.levels = {"ERROR_FALLBACK"},
+		.callback = cmd_ERROR_FALLBACK_cb
+	},
 	{
 		.levels = {"CHARData"},
 		.params = {SCPI_DT_CHARDATA, SCPI_DT_INT},

include/scpi_builtins.h

@@ -2,17 +2,17 @@
 #include <stdint.h>
 #include <stdbool.h>
 
-/** *CLS command callback - clear non-SCPI device state */
+/** Optional *CLS command callback - clear non-SCPI device state */
 extern __attribute__((weak)) void scpi_user_CLS(void);
 
-/** *RST command callback - reset non-SCPI device state */
+/** Optional *RST command callback - reset non-SCPI device state */
 extern __attribute__((weak)) void scpi_user_RST(void);
 
-/** *TST? command callback - perform self test and send response back. */
-extern __attribute__((weak)) void scpi_user_TSTq(void);
+/** Optional *TST? command callback - perform self test and send response back. */
+extern __attribute__((weak)) void scpi_user_TST(void);
 
-/** Get device *IDN? string. */
-extern const char *scpi_device_identifier(void);
+/** MANDATORY callback to get the device *IDN? string. */
+extern const char *scpi_user_IDN(void);
 
 // Provides:
 // const SCPI_command_t scpi_commands_builtin[];

include/scpi_errors.h

@@ -10,6 +10,12 @@ typedef struct {
 /** User error definitions */
 extern const SCPI_error_desc scpi_user_errors[];
 
+
+/** Callback when error is added to the queue */
+extern __attribute__((weak))
+void scpi_user_error(int16_t errno, const char * msg);
+
+
 // SCPI error constants
 enum {
 	E_NO_ERROR = 0,
@@ -137,17 +143,18 @@ enum {
 };
 
 
-/** Get SCPI error message (alone) */
-const char *scpi_error_message(int16_t errno);
-
 
 /**
- * Get SCPI error string for reporting:
+ * Get SCPI error string:
  * <code>,"<message>[; <extra>]"
  *
- * extra can be NULL to skip the optional part.
+ * @param buffer Buffer for storing the final string. Make sure it's big enough.
+ * @param errno Error number
+ * @param extra Extra information, appended after the generic message. Can be NULL.
+ *
+ * @returns actual error code. Code may be coerced to closest defined code (categories: tens, hundreds)
  */
-void scpi_error_string(char *buffer, int16_t errno, const char *extra);
+int16_t scpi_error_string(char *buffer, int16_t errno, const char *extra);
 
 
 /** Add error to the error queue */

include/scpi_parser.h

@@ -61,10 +61,10 @@ typedef struct {
 
 // ---------------- USER CONFIG ----------------
 
-// Zero terminated command struct array - must be defined.
+/** Zero terminated command struct array - must be defined. */
 extern const SCPI_command_t scpi_commands[];
 
-// provided by scpi_builtins.h
+/** Built-in SCPI commands, provided by scpi_builtins.h */
 extern const SCPI_command_t scpi_commands_builtin[];
 
 /** Send a byte to master (may be buffered) */

include/scpi_regs.h

@@ -99,6 +99,16 @@ extern SCPI_REG_STB_t SCPI_REG_STB;
 extern SCPI_REG_STB_t SCPI_REG_SRE; // SRE
 
 
+/** Update the status registers (perform propagation) */
 void scpi_status_update(void);
 
-extern __attribute__((weak)) void scpi_service_request_impl(void);
+
+/**
+ * Service Request callback.
+ * User may choose to implement it (eg. send request to master),
+ * or leave unimplemented.
+ *
+ * SRQ is issued when an event enabled in the status registers (namely SRE) occurs.
+ * See the SCPI spec for details.
+ */
+extern __attribute__((weak)) void scpi_user_SRQ(void);

scpi.pro

@@ -23,7 +23,8 @@ DISTFILES += \
 	.gitignore \
 	LICENSE \
 	README.md \
-	Makefile
+	Makefile \
+    example/Makefile
 
 HEADERS += \
 	source/scpi_parser.h \

source/scpi_builtins.c

@@ -46,8 +46,8 @@ static void builtin_TSTq(const SCPI_argval_t *args)
 {
 	(void)args;
 
-	if (scpi_user_TSTq) {
-		scpi_user_TSTq();
+	if (scpi_user_TST) {
+		scpi_user_TST();
 	}
 }
 
@@ -56,7 +56,7 @@ static void builtin_IDNq(const SCPI_argval_t *args)
 {
 	(void)args;
 
-	scpi_send_string(scpi_device_identifier());
+	scpi_send_string(scpi_user_IDN());
 }
 
 

source/scpi_errors.c

@@ -13,7 +13,7 @@
 // --- queue impl ---
 
 
-static struct {
+static struct ErrorQueueStruct {
 	char queue[ERR_QUEUE_LEN][MAX_ERROR_LEN + 1];
 	int8_t r_pos;
 	int8_t w_pos;
@@ -35,7 +35,13 @@ void scpi_add_error(int16_t errno, const char *extra)
 		}
 	}
 
-	scpi_error_string(erq.queue[erq.w_pos], errno, extra);
+	// get string & coerce errno to valid value
+	errno = scpi_error_string(erq.queue[erq.w_pos], errno, extra);
+
+	// run optional user error callback
+	if (scpi_user_error) {
+		scpi_user_error(errno, erq.queue[erq.w_pos]);
+	}
 
 	erq.w_pos++;
 	erq.count++;
@@ -106,8 +112,55 @@ uint8_t scpi_error_count(void)
 
 // ---- table ----
 
-static const SCPI_error_desc error_table[] = {
+static const SCPI_error_desc no_error_desc = {0, "No error"};
+
+static const SCPI_error_desc scpi_std_errors[] = {
 	{ -100, "Command error"},
+	{ -110, "Command header error"},
+	{ -120, "Numeric data error"},
+	{ -130, "Suffix error"},
+	{ -140, "Character data error"},
+	{ -150, "String data error"},
+	{ -160, "Block data error"},
+	{ -170, "Expression error"},
+	{ -180, "Macro error"},
+	{ -200, "Execution error"},
+
+	{ -210, "Trigger error"},
+	{ -220, "Parameter error"},
+	{ -230, "Data corrupt or stale"},
+	{ -240, "Hardware error"},
+	{ -250, "Mass storage error"},
+	{ -260, "Expression error"},
+	{ -270, "Macro error"},
+	{ -280, "Program error"},
+	{ -290, "Memory use error"},
+
+	{ -300, "Device-specific error"},
+	{ -310, "System error"},
+	{ -320, "Storage fault"},
+	{ -330, "Self-test failed"},
+	{ -340, "Calibration failed"},
+	{ -350, "Queue overflow"},
+	{ -360, "Communication error"},
+
+	{ -400, "Query error"},
+
+	// Error codes that don't make much sense
+#ifdef SCPI_WEIRD_ERRORS
+	{ -410, "Query INTERRUPTED"},
+	{ -420, "Query UNTERMINATED"},
+	{ -430, "Query DEADLOCKED"},
+	{ -440, "Query UNTERMINATED after indefinite response"},
+	{ -500, "Power on"},
+	{ -600, "User request"},
+	{ -700, "Request control"},
+	{ -800, "Operation complete"},
+#endif
+
+	// Fine error codes.
+	// Turn off to save space
+#ifdef SCPI_FINE_ERRORS
 	{ -101, "Invalid character"},
 	{ -102, "Syntax error"},
 	{ -103, "Invalid separator"},
@@ -115,62 +168,62 @@ static const SCPI_error_desc error_table[] = {
 	{ -105, "GET not allowed"},
 	{ -108, "Parameter not allowed"},
 	{ -109, "Missing parameter"},
-	{ -110, "Command header error"},
+
 	{ -111, "Header separator error"},
 	{ -112, "Program mnemonic too long"},
 	{ -113, "Undefined header"},
 	{ -114, "Header suffix out of range"},
 	{ -115, "Unexpected number of parameters"},
-	{ -120, "Numeric data error"},
+
 	{ -121, "Invalid character in number"},
 	{ -123, "Exponent too large"},
 	{ -124, "Too many digits"},
 	{ -128, "Numeric data not allowed"},
-	{ -130, "Suffix error"},
+
 	{ -131, "Invalid suffix"},
 	{ -134, "Suffix too long"},
 	{ -138, "Suffix not allowed"},
-	{ -140, "Character data error"},
+
 	{ -141, "Invalid character data"},
 	{ -144, "Character data too long"},
 	{ -148, "Character data not allowed"},
-	{ -150, "String data error"},
+
 	{ -151, "Invalid string data"},
 	{ -158, "String data not allowed"},
-	{ -160, "Block data error"},
+
 	{ -161, "Invalid block data"},
 	{ -168, "Block data not allowed"},
-	{ -170, "Expression error"},
+
 	{ -171, "Invalid expression"},
 	{ -178, "Expression data not allowed"},
-	{ -180, "Macro error"},
+
 	{ -181, "Invalid outside macro definition"},
 	{ -183, "Invalid inside macro definition"},
 	{ -184, "Macro parameter error"},
-	{ -200, "Execution error"},
+
 	{ -201, "Invalid while in local"},
 	{ -202, "Settings lost due to rtl"},
 	{ -203, "Command protected"},
-	{ -210, "Trigger error"},
+
 	{ -211, "Trigger ignored"},
 	{ -212, "Arm ignored"},
 	{ -213, "Init ignored"},
 	{ -214, "Trigger deadlock"},
 	{ -215, "Arm deadlock"},
-	{ -220, "Parameter error"},
+
 	{ -221, "Settings conflict"},
 	{ -222, "Data out of range"},
 	{ -223, "Too much data"},
 	{ -224, "Illegal parameter value"},
 	{ -225, "Out of memory"},
 	{ -226, "Lists not same length"},
-	{ -230, "Data corrupt or stale"},
+
 	{ -231, "Data questionable"},
 	{ -232, "Invalid format"},
 	{ -233, "Invalid version"},
-	{ -240, "Hardware error"},
+
 	{ -241, "Hardware missing"},
-	{ -250, "Mass storage error"},
+
 	{ -251, "Missing mass storage"},
 	{ -252, "Missing media"},
 	{ -253, "Corrupt media"},
@@ -179,9 +232,9 @@ static const SCPI_error_desc error_table[] = {
 	{ -256, "File name not found"},
 	{ -257, "File name error"},
 	{ -258, "Media protected"},
-	{ -260, "Expression error"},
+
 	{ -261, "Math error in expression"},
-	{ -270, "Macro error"},
+
 	{ -271, "Macro syntax error"},
 	{ -272, "Macro execution error"},
 	{ -273, "Illegal macro label"},
@@ -190,105 +243,113 @@ static const SCPI_error_desc error_table[] = {
 	{ -276, "Macro recursion error"},
 	{ -277, "Macro redefinition not allowed"},
 	{ -278, "Macro header not found"},
-	{ -280, "Program error"},
+
 	{ -281, "Cannot create program"},
 	{ -282, "Illegal program name"},
 	{ -283, "Illegal variable name"},
 	{ -284, "Program currently running"},
 	{ -285, "Program syntax error"},
 	{ -286, "Program runtime error"},
-	{ -290, "Memory use error"},
+
 	{ -291, "Out of memory"},
 	{ -292, "Referenced name does not exist"},
 	{ -293, "Referenced name already exists"},
 	{ -294, "Incompatible type"},
-	{ -300, "Device-specific error"},
-	{ -310, "System error"},
+
 	{ -311, "Memory error"},
 	{ -312, "PUD memory lost"},
 	{ -313, "Calibration memory lost"},
 	{ -314, "Save/recall memory lost"},
 	{ -315, "Configuration memory lost"},
-	{ -320, "Storage fault"},
+
 	{ -321, "Out of memory"},
-	{ -330, "Self-test failed"},
-	{ -340, "Calibration failed"},
-	{ -350, "Queue overflow"},
-	{ -360, "Communication error"},
 	{ -361, "Parity error in program message"},
 	{ -362, "Framing error in program message"},
 	{ -363, "Input buffer overrun"},
 	{ -365, "Time out error"},
-	{ -400, "Query error"},
-	{ -410, "Query INTERRUPTED"},
-	{ -420, "Query UNTERMINATED"},
-	{ -430, "Query DEADLOCKED"},
-	{ -440, "Query UNTERMINATED after indefinite response"},
-	{ -500, "Power on"},
-	{ -600, "User request"},
-	{ -700, "Request control"},
-	{ -800, "Operation complete"},
+#endif
+
 	{0} // end mark
 };
 
 
-const char * scpi_error_message(int16_t errno)
+static const SCPI_error_desc * find_error_desc(const SCPI_error_desc *table, int16_t errno)
 {
+	for (int i = 0; (i == 0 || table[i].errno != 0); i++) {
+		if (table[i].errno == errno) {
+			return &table[i];
+		}
+	}
+
+	return NULL;
+}
+
+
+static const SCPI_error_desc * resolve_error_desc(int16_t errno)
+{
+	const SCPI_error_desc *desc;
+
 	if (errno == 0) {
 		// ok state
-		return "No error";
+		return &no_error_desc;
 
 	} else if (errno < 0) {
 		// standard errors
-		for (int i = 0; (i == 0 || error_table[i].errno != 0); i++) {
-			if (error_table[i].errno == errno) {
-				return error_table[i].msg;
-			}
-		}
+
+		desc = find_error_desc(scpi_std_errors, errno);
+		if (desc != NULL) return desc;
+
+		// not found in table, use group-common error
+		errno += -errno % 10; // round to ten
+
+		desc = find_error_desc(scpi_std_errors, errno);
+		if (desc != NULL) return desc;
+
+		errno += -errno % 100; // round to hundred
+
+		desc = find_error_desc(scpi_std_errors, errno);
+		if (desc != NULL) return desc;
 
 	} else {
 		// user error
-		for (int i = 0; scpi_user_errors[i].errno != 0; i++) {
-			if (scpi_user_errors[i].errno == errno) {
-				return scpi_user_errors[i].msg;
-			}
-		}
+
+		desc = find_error_desc(scpi_user_errors, errno);
+		if (desc != NULL) return desc;
 	}
 
-	return "Unknown error";
+	return NULL;
 }
 
 
-void scpi_error_string(char *buffer, int16_t errno, const char *extra)
+/**
+ * Get error string.
+ *
+ * @param buffer Buffer for storing the final string. Make sure it's big enough.
+ * @param errno Error number
+ * @param extra Extra information, appended after the generic message.
+ *
+ * @returns actual error code. Code may be coerced to closest defined code (categories: tens, hundreds)
+ */
+int16_t scpi_error_string(char *buffer, int16_t errno, const char *extra)
 {
-	const char *msg = scpi_error_message(errno);
+	const SCPI_error_desc *desc = resolve_error_desc(errno);
+	const char *msg;
 
-	// len - total length, offs - current segment length
-	int len, offs;
-
-	len = offs = sprintf(buffer, "%d,\"", errno); // <code>,"
-	buffer += offs;
-
-	offs = sprintf(buffer, "%s", msg); // Error message
-	len += offs;
-	buffer += offs;
-
-	if (extra != NULL) {
-		// extra info
-		offs = sprintf(buffer, "; "); // ;
-		len += offs;
-		buffer += offs;
-
-		// copy in the extra string
-		int ll = 250 - len - 2;
-		int xlen = strlen(extra);
-		if (ll > xlen) ll = xlen;
-		strncpy(buffer, extra, ll); // Extra msg
+	if (desc != NULL) {
+		errno = desc->errno;
+		msg = desc->msg;
+	} else {
+		// bad error code
+		msg = "Unknown error";
+	}
 
-		len += ll;
-		buffer += ll;
+	// Print.
+	if (extra == NULL) {
+		sprintf(buffer, "%d,\"%s\"", errno, msg);
+	} else {
+		sprintf(buffer, "%d,\"%s; %s\"", errno, msg, extra);
 	}
 
-	sprintf(buffer, "\""); // "
+	return errno;
 }
 

source/scpi_regs.c

@@ -35,8 +35,8 @@ void scpi_status_update(void)
 
 	// Run service request callback
 	if (SCPI_REG_STB.RQS) {
-		if (scpi_service_request_impl) {
-			scpi_service_request_impl();
+		if (scpi_user_SRQ) {
+			scpi_user_SRQ();
 		}
 	}
 }