more sensible warnings if hardware is missing

1 files changed, 44 insertions, 3 deletions

diff --git a/gpib.c b/gpib.c
index 1606eea..7b42939 100644
--- a/gpib.c
+++ b/gpib.c
@@ -240,6 +240,8 @@
 
 /* TNT4882 GLOBAL VARIABLES -------------------------------------------------*/
 
+int is_gpib;
+
 int INTERFACE_ERROR;				/* Error Code */
 int INTERFACE_STATUS;				/* Interface Status */
 unsigned char MR_4882_status[5];		/* 4882 status memory registers */
@@ -424,6 +426,15 @@ void GPIB_initialize(void)
 	TNT_Out(R_cmdr,F_softreset);	/* Reset FIFOS */
 
 	TNT_Out(R_spmr ,0x80);		/* This sequence of commands */
+
+	if (TNT_In(R_spmr) == 0x80) {
+		is_gpib = 1;
+	} else {
+		is_gpib = 0;
+		printf ("Error: TNT4882 chip not found\n");
+		return;
+	}
+
 	TNT_Out(R_auxmr,0x80);		/*	insures that the TNT */
 	TNT_Out(R_auxmr,0x99);		/*	will be in the normal 7210 */
 	TNT_Out(R_keyrg,0);		/*	mode and not 9914 */
@@ -468,6 +479,8 @@ static void TNT_Adr_Mode()
 
 void GPIB_change_address(int new_address)
 {
+	if (!is_gpib) return;
+
 	int eprom_loc;
 
 	TNT_Out(R_adr,new_address);		/* Load new address setting */
@@ -622,6 +635,8 @@ int GPIB_check_for_device_clear_signal(void)
 	/* added by MJC - June 20/06 */
 	/* reset interface if a device clear is received */
 
+        if (!is_gpib) return FALSE;
+
 	if (TNT_INT_STATUS() & DCAS) {
 		TNT_Out(R_auxmr,F_clrDEC);
 		TNT_INT_STATUS();
@@ -636,6 +651,8 @@ int GPIB_check_for_messages(char *gpib_buf)
 {
 #define ib_empty  (!(strlen(gpib_buf)))
 
+        if (!is_gpib) return FALSE;
+
 	/* If the GPIB has requested data, and no output messages are in the TNT4882 FIFOs, generate a query error */
 	if (TNT_update_brq() && !TNT_input_bav() && ib_empty) {
 		queue_error_for_gpib_only(query_error_unterminated);
@@ -664,6 +681,8 @@ int GPIB_check_for_messages(char *gpib_buf)
 
 int GPIB_handle_new_input(char *gpib_buf)
 {
+        if (!is_gpib) return FALSE;
+
 	/* read until done or buffers empty. Then reset DAC holdoff */
 
 	unsigned long int count_sent;		/* Local count variable */
@@ -748,6 +767,8 @@ static void TNT_Holdoff_off()
 
 int GPIB_send_query_response(char *out_buffer)
 {
+        if (!is_gpib) return OK;
+
 	/* message must be available if this function has been called */
 
 	unsigned long int out_cnt;
@@ -871,6 +892,7 @@ int GPIB_send_query_response(char *out_buffer)
 void GPIB_check_remote_status (int *is_remote, int *is_lockout)
 {
 	*is_remote = *is_lockout = 0;
+        if (!is_gpib) return;
 
 	TNT_INT_STATUS();					/* Update to get current status */
 	if ((INTERFACE_STATUS&REM) == REM) {
@@ -886,12 +908,16 @@ void GPIB_check_remote_status (int *is_remote, int *is_lockout)
 
 unsigned char GPIB_response_already_pending ()
 {
+        if (!is_gpib) return 0;
+
 	return TNT_In(R_spsr) & 0x10;
 }
 
 
 void GPIB_go_to_local ()
 {
+        if (!is_gpib) return;
+
 	TNT_Out(R_auxmr,0x05);		/* issue TNT rtl command */
 	return;
 }
@@ -899,6 +925,8 @@ void GPIB_go_to_local ()
 
 void GPIB_clear_events ()
 {
+        if (!is_gpib) return;
+
 	TNT_4882_Status(ESR,0xff,CLEAR);	/* Clear ESR register */
 	TNT_4882_Status(STB,0x20,CLEAR);	/* Clear ESB bit in STB */
 	return;
@@ -925,51 +953,64 @@ unsigned int GPIB_get_ESE ()
 
 unsigned int GPIB_get_STB ()
 {
+        if (!is_gpib) return;
+
 	return (TNT_In(R_spsr)&0xbf) | (((TNT_In(R_spsr)&0xbf) & MR_4882_status[SRE])?0x40:0);
 }
 
 
 void GPIB_set_ESR (unsigned int byte,int operation)
 {
+        if (!is_gpib) return;
+
 	TNT_4882_Status(ESR,byte,operation);
-	return;
 }
 
 
 void GPIB_set_SRE (unsigned int byte,int operation)
 {
+        if (!is_gpib) return;
+
 	TNT_4882_Status(SRE,byte,operation);
-	return;
 }
 
 
 void GPIB_set_ESE (unsigned int byte,int operation)
 {
+        if (!is_gpib) return;
+
 	TNT_4882_Status(ESE,byte,operation);
-	return;
 }
 
 
 void GPIB_Set_Execution_Error ()
 {
+        if (!is_gpib) return;
+
 	TNT_4882_Status(3,0x10,1);
 }
 
 
 void GPIB_Set_Command_Error ()
 {
+        if (!is_gpib) return;
+
 	TNT_4882_Status(3,0x20,1);
 }
 
 
 void GPIB_Set_Query_Error ()
 {
+        if (!is_gpib) return;
+
 	TNT_4882_Status(3,0x04,1);
 }
 
 
 void GPIB_Set_Device_Dependent_Error ()
 {
+        if (!is_gpib) return;
+
 	TNT_4882_Status(3,0x08,1);
 }