Started deep sleep command

src/lib.rs

@@ -155,4 +155,14 @@ impl<BusyPin: InputPin, ResetPin: OutputPin, DcPin: OutputPin, Spi: SpiDevice, D
         self.delay.delay_ms(1);
         self.wait_for_display();
     }
+
+    /// Puts the display into deep sleep mode which effectively deinitialises the display controller.
+    /// 
+    /// Reinitialising the display with [EPaperDisplay::new] is sufficient to wake the display back up.
+    /// 
+    /// All display controller registers will be reset by this process.
+    pub fn deep_sleep(mut self) {
+        self.write_command(0x07);
+        self.write_data(0xA5);
+    }
 }