diff --git a/buspirate_spi.c b/buspirate_spi.c
index d2ebc75..9d229f4 100644
--- a/buspirate_spi.c
+++ b/buspirate_spi.c
@@ -286,7 +286,7 @@
 		/* The Bus Pirate can't handle UART input buffer overflow in BBIO mode, and sending a sequence
 		 * of 0x00 too fast apparently triggers such an UART input buffer overflow.
 		 */
-		usleep(10000);
+		internal_sleep(10000);
 	}
 	/* We know that 20 commands of \0 should elicit at least one BBIO1 response. */
 	if ((ret = buspirate_wait_for_string(bp_commbuf, "BBIO")))
diff --git a/programmer.h b/programmer.h
index a22bdd2..2ea7b48 100644
--- a/programmer.h
+++ b/programmer.h
@@ -250,6 +250,7 @@
 /* udelay.c */
 void myusec_delay(int usecs);
 void myusec_calibrate_delay(void);
+void internal_sleep(int usecs);
 void internal_delay(int usecs);
 
 #if CONFIG_INTERNAL == 1
diff --git a/udelay.c b/udelay.c
index 9f5e562..e3cf3e3 100644
--- a/udelay.c
+++ b/udelay.c
@@ -169,13 +169,23 @@
 	msg_pinfo("OK.\n");
 }
 
+/* Not very precise sleep. */
+void internal_sleep(int usecs)
+{
+#ifdef _WIN32
+	Sleep((usecs + 999) / 1000);
+#else
+	sleep(usecs / 1000000);
+	usleep(usecs % 1000000);
+#endif
+}
+
+/* Precise delay. */
 void internal_delay(int usecs)
 {
-	/* If the delay is >1 s, use usleep because timing does not need to
-	 * be so precise.
-	 */
+	/* If the delay is >1 s, use internal_sleep because timing does not need to be so precise. */
 	if (usecs > 1000000) {
-		usleep(usecs);
+		internal_sleep(usecs);
 	} else {
 		myusec_delay(usecs);
 	}