use CLEAR instead of usb_reset to recover from errors

diff --git a/usbtmc.c b/usbtmc.c
index 2ccbf897ca4617a51e514a65c03f4d6804c8ed73..ffebcbff952b82dc2a4b358f6d8cf1e6166b9fee 100644 (file)
--- a/usbtmc.c
+++ b/usbtmc.c
@@ -7,7 +7,7 @@
 #include "scope.h"
 #include "usbtmc.h"
 
-#define USB_TIMEOUT 50000
+#define USB_TIMEOUT 10000
 
 #if BYTE_ORDER == LITTLE_ENDIAN
 #define LE32(x) x
@@ -18,7 +18,7 @@
 #endif
 
 /* TODO: fix memory leak here: */
-#define USB_ERROR(s, x) do { if (x < 0) { fprintf(stderr, "usb %s: %s\n", s, usb_strerror()); usb_reset(sc->usb.dev); return 0; } } while(0)
+#define USB_ERROR(s, x) do { if (x < 0) { fprintf(stderr, "usb %s: %s\n", s, usb_strerror()); usbtmc_clear(sc); return 0; } } while(0)
 
 /* This routine locates a scope by VID/PID and returns a struct scope* for it */
 static struct scope* usbtmc_find_scope() {
@@ -133,6 +133,43 @@ static struct usbtmc_capabilities* usbtmc_get_capabilities(struct scope *sc)
        return &res;
 }
 
+static void usbtmc_clear(struct scope *sc)
+{
+       int r;
+       unsigned char status[2];
+
+       printf("Initiating clear...\n");
+       r = usb_control_msg(sc->usb.dev, 0xA1,
+               USBTMC_CTL_INITIATE_CLEAR,
+               0, 0, (char*)status, 1,
+               USB_TIMEOUT);
+       
+       if ((r != 1) || status[0] != 0x01) {
+               printf("INITIATE_CLEAR failed: %s\n", usb_strerror());
+               return;
+       }
+
+       while(1) {
+               usleep(100000);
+               printf("Waiting for clear to complete...\n");
+
+               r = usb_control_msg(sc->usb.dev, 0xA1,
+                       USBTMC_CTL_CHECK_CLEAR_STAT,
+                       0, 0, (char*)status, 2,
+                       USB_TIMEOUT);
+
+               if ((r != 2) || status[0] != 0x01) {
+                       printf("CHECK_CLEAR failed: %s\n", usb_strerror());
+                       return;
+               }
+
+               if (status[1] & (1<<0)) {
+                       printf("Success!\n");
+                       break;
+               }
+       }
+}
+
 /*
  * Send a scpi-command to the scope. The response goes into the buffer
  * called resp, with a size of resplen. If resp==NULL, no response