[tools] update dfu script

- add a timeout so you have time to connect the device
- less verbose, don't print all addresses

sw/tools/dfu/stm32_mem.py

@@ -29,6 +29,7 @@ from optparse import OptionParser
 
 import usb
 import dfu
+import time
 
 APP_ADDRESS = 0x08002000
 SECTOR_SIZE = 2048
@@ -101,7 +102,13 @@ if __name__ == "__main__":
     if options.verbose:
         print_copyright()
 
-    devs = dfu.finddevs()
+    for i in range(1,60):
+      devs = dfu.finddevs()
+      if not devs:
+        print('.', end="")
+        stdout.flush()
+        time.sleep(0.5)
+    print("")
     if not devs:
         print("No DFU devices found!")
         exit(1)
@@ -186,8 +193,11 @@ if __name__ == "__main__":
 
     #addr = APP_ADDRESS
     addr = options.addr
+    print ("Programming memory from 0x%08X...\r" % addr)
+    
     while bin:
-        print("Programming memory at 0x%08X\r" % addr)
+#        print("Programming memory at 0x%08X\r" % addr),
+        print('#', end="")
         stdout.flush()
         stm32_erase(target, addr)
         stm32_write(target, bin[:SECTOR_SIZE])