Merge pull request #35 from mariovisic/nice_to_cpu

Reduce the CPU load when waiting for the display

Author: makermelissa

adafruit_epd/epd.py

@@ -72,7 +72,7 @@ def __init__(self, width, height, spi, cs_pin, dc_pin, sramcs_pin, rst_pin, busy
         # SPI interface (required)
         self.spi_device = spi
         while not self.spi_device.try_lock():
-            pass
+            time.sleep(0.01)
         self.spi_device.configure(baudrate=1000000) # 1 Mhz
         self.spi_device.unlock()
 
@@ -99,7 +99,7 @@ def display(self):  # pylint: disable=too-many-branches
 
         if self.sram:
             while not self.spi_device.try_lock():
-                pass
+                time.sleep(0.01)
             self.sram.cs_pin.value = False
             #send read command
             self._buf[0] = mcp_sram.Adafruit_MCP_SRAM.SRAM_READ
@@ -114,7 +114,7 @@ def display(self):  # pylint: disable=too-many-branches
         databyte = self.write_ram(0)
 
         while not self.spi_device.try_lock():
-            pass
+            time.sleep(0.01)
         self._dc.value = True
 
         if self.sram:
@@ -131,7 +131,7 @@ def display(self):  # pylint: disable=too-many-branches
 
         if self.sram:
             while not self.spi_device.try_lock():
-                pass
+                time.sleep(0.01)
             self.sram.cs_pin.value = False
             #send read command
             self._buf[0] = mcp_sram.Adafruit_MCP_SRAM.SRAM_READ
@@ -147,7 +147,7 @@ def display(self):  # pylint: disable=too-many-branches
             databyte = self.write_ram(1)
 
             while not self.spi_device.try_lock():
-                pass
+                time.sleep(0.01)
             self._dc.value = True
 
             if self.sram:
@@ -182,7 +182,7 @@ def command(self, cmd, data=None, end=True):
         self._cs.value = False
 
         while not self.spi_device.try_lock():
-            pass
+            time.sleep(0.01)
         ret = self._spi_transfer(cmd)
 
         if data is not None:

adafruit_epd/il0373.py

@@ -96,7 +96,7 @@ def busy_wait(self):
         busy pin, or pausing"""
         if self._busy:
             while not self._busy.value:
-                pass
+                time.sleep(0.01)
         else:
             time.sleep(0.5)
 

adafruit_epd/il91874.py

@@ -105,7 +105,7 @@ def busy_wait(self):
         busy pin, or pausing"""
         if self._busy:
             while not self._busy.value:
-                pass
+                time.sleep(0.01)
         else:
             time.sleep(0.5)