diff --git a/cntr/fw/cntr/cntr.c b/cntr/fw/cntr/cntr.c
index 9f0bf54..b7815ec 100644
--- a/cntr/fw/cntr/cntr.c
+++ b/cntr/fw/cntr/cntr.c
@@ -22,7 +22,7 @@
 
 
 uint8_t cntr[4];
-enum hw_type hw_type = HW_TYPE_V1;
+enum hw_type hw_type;
 
 
 static void delay(unsigned ms)
@@ -37,17 +37,22 @@ static void delay(unsigned ms)
 
 static void init_io(void)
 {
-	if (VERSION_ID) {
-		/* flash LED a second time */
+	int i;
+
+	/* SDCC bug - needs parentheses here */
+	hw_type = VERSION_ID1 ?
+	    (VERSION_ID2 ? HW_TYPE_V2 : HW_TYPE_V3) :
+	    HW_TYPE_V1;
+
+	for (i = HW_TYPE_V1; i != hw_type; i++) {
+		/* flash LED a second or third time */
 		LEDv2 = 0;
 		delay(250);
 		LEDv2 = 1;
 		delay(250);
-
-		PROBE_TERM_MODE |= 1 << PROBE_TERM_BIT;
-
-		hw_type = HW_TYPE_V2;
 	}
+	if (hw_type == HW_TYPE_V2)
+		PROBE_TERM_MODE |= 1 << PROBE_TERM_BIT;
 
 	/*
 	 * Signal	Mode		Value
@@ -70,7 +75,7 @@ static void init_io(void)
 	P2 = 0;
 	P3 = 0;
 
-	if (hw_type == HW_TYPE_V2)
+	if (hw_type == HW_TYPE_V2 || hw_type == HW_TYPE_V3)
 		PROBE_TERM = 1;
 
 	/*
diff --git a/cntr/fw/cntr/cntr.h b/cntr/fw/cntr/cntr.h
index db248c8..b70340b 100644
--- a/cntr/fw/cntr/cntr.h
+++ b/cntr/fw/cntr/cntr.h
@@ -25,6 +25,7 @@ extern uint8_t cntr[4];
 extern enum hw_type {
 	HW_TYPE_V1 = 0,
 	HW_TYPE_V2 = 1,
+	HW_TYPE_V3 = 2,
 } hw_type;
 
 #endif /* !CNTR_H */
diff --git a/cntr/fw/common/io.h b/cntr/fw/common/io.h
index 6b798dd..52409c4 100644
--- a/cntr/fw/common/io.h
+++ b/cntr/fw/common/io.h
@@ -30,6 +30,7 @@
  *
  * - v1: 100 kOhm termination (not very useful)
  * - v2: pull-up for input amplifier
+ * - v3: 330 Ohm termination
  */
 
 #define	PROBE_TERM	P1_2
@@ -40,8 +41,20 @@
  * In version 1, P2_1 is used to provide ground to the input side. In version
  * 2, we use a ground place for this and P2_1 is unconnected. We can therefore
  * use it to identify the hardware version.
+ *
+ * In version 3, P2_0 is connected to ground. In all other versions, it is
+ * unconnected.
+ *
+ * Board  VERSION_ID1
+ *        | VERSION_ID2
+ *        | |
+ * v1     0 Z
+ * v2     Z Z
+ * v3     Z 0
+ * 
  */
 
-#define	VERSION_ID	P2_1
+#define	VERSION_ID1	P2_1
+#define	VERSION_ID2	P2_0
 
 #endif /* !IO_H */