modify convertor to add temperature units toggler

converters/lywsd03mmc.js

@@ -1,4 +1,5 @@
 const fz = require('zigbee-herdsman-converters/converters/fromZigbee');
+const tz = require('zigbee-herdsman-converters/converters/toZigbee');
 const exposes = require('zigbee-herdsman-converters/lib/exposes');
 const reporting = require('zigbee-herdsman-converters/lib/reporting');
 const ota = require('zigbee-herdsman-converters/lib/ota');
@@ -9,8 +10,8 @@ const definition = {
     model: 'LYWSD03MMC',
     vendor: 'Xiaomi',
     description: 'Temperature & humidity sensor',
-    fromZigbee: [fz.temperature, fz.humidity, fz.battery],
-    toZigbee: [],
+    fromZigbee: [fz.temperature, fz.humidity, fz.battery, fz.hvac_user_interface],
+    toZigbee: [tz.thermostat_temperature_display_mode],
     configure: async (device, coordinatorEndpoint, logger) => {
         const endpoint = device.getEndpoint(1);
         const bindClusters = ['msTemperatureMeasurement', 'msRelativeHumidity', 'genPowerCfg'];
@@ -20,7 +21,11 @@ const definition = {
         await reporting.batteryVoltage(endpoint);
         await reporting.batteryPercentageRemaining(endpoint);
     },
-    exposes: [e.temperature(), e.humidity(), e.battery()],
+    exposes: [
+        e.temperature(), e.humidity(), e.battery(),
+        exposes.enum('temperature_display_mode', exposes.access.ALL, ['celsius', 'fahrenheit'])
+        .withDescription('The temperature format displayed on the screen'),
+    ],
     ota: ota.zigbeeOTA,
 };