Implement MMU hw reset

Firmware/mmu2.cpp

@@ -98,6 +98,11 @@ MMU2::MMU2()
 }
 
 void MMU2::Start() {
+#ifdef MMU_HWRESET
+    WRITE(MMU_RST_PIN, 1);
+    SET_OUTPUT(MMU_RST_PIN); // setup reset pin
+#endif //MMU_HWRESET
+
     mmu2Serial.begin(MMU_BAUD);
 
     PowerOn();

Firmware/mmu2_power.cpp

@@ -1,4 +1,8 @@
 #include "mmu2_power.h"
+#include "Configuration_prusa.h"
+#include "pins.h"
+#include "fastio.h"
+#include <util/delay.h>
 
 namespace MMU2 {
 
@@ -7,6 +11,15 @@ void power_on() { }
 
 void power_off() { }
 
-void reset() { }
+void reset() {
+#ifdef MMU_HWRESET // HW - pulse reset pin
+    WRITE(MMU_RST_PIN, 0);
+    _delay_us(100);
+    WRITE(MMU_RST_PIN, 1);
+#else // SW - send X0 command
+    // mmu_puts_P(PSTR("X0\n"));
+    #error todo send command if hardware pin not available
+#endif
+}
 
 } // namespace MMU2