diff --git a/clock.c b/clock.c
index 081b1f9c0..06ea57499 100644
--- a/clock.c
+++ b/clock.c
@@ -94,6 +94,7 @@ static void clock_250ms(void) {
     #endif
 
     temp_residency_tick();
+    temp_periodic_print();
 
     if (temp_waiting()) {
       serial_writestr_P(PSTR("Waiting for target temp\n"));
diff --git a/gcode_process.c b/gcode_process.c
index c202246e2..d670f7150 100644
--- a/gcode_process.c
+++ b/gcode_process.c
@@ -644,7 +644,12 @@ void process_gcode_command() {
 				//?  FIRMWARE_NAME:Teacup FIRMWARE_URL:http://github.com/traumflug/Teacup_Firmware/ PROTOCOL_VERSION:1.0 MACHINE_TYPE:Mendel EXTRUDER_COUNT:1 TEMP_SENSOR_COUNT:1 HEATER_COUNT:1
 				//?
 
-				sersendf_P(PSTR("FIRMWARE_NAME:Teacup FIRMWARE_URL:http://github.com/traumflug/Teacup_Firmware/ PROTOCOL_VERSION:1.0 MACHINE_TYPE:Mendel EXTRUDER_COUNT:%d TEMP_SENSOR_COUNT:%d HEATER_COUNT:%d\n"), 1, NUM_TEMP_SENSORS, NUM_HEATERS);
+        sersendf_P(PSTR("FIRMWARE_NAME:Teacup "
+                        "FIRMWARE_URL:http://github.com/traumflug/Teacup_Firmware/ "
+                        "PROTOCOL_VERSION:1.0 MACHINE_TYPE:Mendel EXTRUDER_COUNT:%d "
+                        "TEMP_SENSOR_COUNT:%d HEATER_COUNT:%d\n"
+                        "cap:AUTOREPORT_TEMP:%d\n"),
+                        1, NUM_TEMP_SENSORS, NUM_HEATERS, 1);
 				break;
 
 			case 116:
@@ -790,6 +795,35 @@ void process_gcode_command() {
 				#endif
 				break;
 
+      case 155:
+        //? --- M155: Report Temperature(s) Periodically ---
+        //?
+        //? Example: M155 Sn
+        //?
+        //? turns on periodic reporting of the temperatures of the current
+        //? extruder and the build base in degrees Celsius. The reporting
+        //? interval is given in seconds as the S parameter. Use S0 to disable
+        //? periodic temperature reporting. The reporting format is the same
+        //? as for M105, except there is no "ok" at the start of each report.
+        //? For example, the line sent to the host periodically looks like
+        //?
+        //? <tt>T:201 B:117</tt>
+        //?
+        //? Teacup supports an optional P parameter as a zero-based temperature
+        //? sensor index to address.
+        //?
+
+        // S<period-seconds> is required
+        if ( ! next_target.seen_S)
+          break;
+        #ifdef ENFORCE_ORDER
+          queue_wait();
+        #endif
+        if ( ! next_target.seen_P)
+          next_target.P = TEMP_SENSOR_none;
+        temp_periodic_config(next_target.S, next_target.P);
+        break;
+
       case 220:
         //? --- M220: Set speed factor override percentage ---
         if ( ! next_target.seen_S)
diff --git a/temp.c b/temp.c
index 10ac04eec..9e36a1fb9 100644
--- a/temp.c
+++ b/temp.c
@@ -108,6 +108,11 @@ static struct {
 static uint8_t wait_for_temp = 0;
 
 
+// Automatic temperature report period (AUTOREPORT_TEMP)
+static uint8_t          periodic_temp_seconds;
+static temp_sensor_t    periodic_temp_index;
+static uint8_t          periodic_temp_timer;
+
 /// Set up temp sensors.
 void temp_init() {
 	temp_sensor_t i;
@@ -626,6 +631,27 @@ static void single_temp_print(temp_sensor_t index) {
   #endif
 }
 
+/// set parameters for periodic temperature reporting
+/// \param secs reporting interval in seconds; 0 to disable reporting
+/// \param index sensor to report
+void temp_periodic_config(uint8_t secs, temp_sensor_t index) {
+  periodic_temp_seconds = secs;
+  periodic_temp_index = index;
+  periodic_temp_timer = secs;
+}
+
+/// send temperatures to the host periodically.
+/// Called once per second from clock.c
+void temp_periodic_print() {
+  if (periodic_temp_seconds == 0)
+    return;
+  if (--periodic_temp_timer != 0)
+    return;
+
+  temp_print(periodic_temp_index);
+  periodic_temp_timer = periodic_temp_seconds;
+}
+
 /// send temperatures to host
 /// \param index sensor value to send
 void temp_print(temp_sensor_t index) {
diff --git a/temp.h b/temp.h
index f5fec4692..ed0c3836a 100644
--- a/temp.h
+++ b/temp.h
@@ -40,6 +40,9 @@ void temp_heater_tick(void);
 
 void temp_residency_tick(void);
 
+void temp_periodic_config(uint8_t secs, temp_sensor_t index);
+void temp_periodic_print(void);
+
 uint8_t	temp_achieved(void);
 
 void temp_set_wait(void);