data into buffer_in

[hackapet/Adafruit_Blinka.git] / src / adafruit_blinka / microcontroller / raspi_23 / spi.py

diff --git a/src/adafruit_blinka/microcontroller/raspi_23/spi.py b/src/adafruit_blinka/microcontroller/raspi_23/spi.py
old mode 100644 (file)
new mode 100755 (executable)
index 7e3eec5..27ead42
--- a/src/adafruit_blinka/microcontroller/raspi_23/spi.py
+++ b/src/adafruit_blinka/microcontroller/raspi_23/spi.py
@@ -66,4 +66,31 @@ class SPI:
             self._spi.close()
         except FileNotFoundError as not_found:
             print("Could not open SPI device - check if SPI is enabled in kernel!")
-            raise
\ No newline at end of file
+            raise
+
+    def write_readinto(self, buffer_out, buffer_in, out_start=0,
+                       out_end=None, in_start=0, in_end=None):
+        if not buffer_out or not buffer_in:
+            return
+        if out_end is None:
+            out_end = len(buffer_out)        
+        if in_end is None:
+            in_end = len(buffer_in)
+        if out_end - out_start != in_end - in_start:
+            raise RuntimeError('Buffer slices must be of equal length.')
+        try:
+            self._spi.open(self._port, 0)
+            try:
+                self._spi.no_cs = True  # this doesn't work but try anyways
+            except AttributeError:
+                pass
+            self._spi.max_speed_hz = self.baudrate
+            self._spi.mode = self.mode
+            self._spi.bits_per_word = self.bits
+            data = self._spi.xfer(list(buffer_out[out_start:out_end+1]))
+            for i in range((in_end - in_start)):
+                buffer_in[i+in_start] = data[i]
+            self._spi.close()
+        except FileNotFoundError as not_found:
+            print("Could not open SPI device - check if SPI is enabled in kernel!")
+            raise