X-Git-Url: https://git.ayoreis.com/Adafruit_Blinka-hackapet.git/blobdiff_plain/5ffe910b4390149bb627219ee5021e15dc1b4e1f..35d5df3e2e925deae07db4f75902b58a3845c90c:/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
index d862e01..b905873 100755
--- a/src/adafruit_blinka/microcontroller/raspi_23/spi.py
+++ b/src/adafruit_blinka/microcontroller/raspi_23/spi.py
@@ -19,9 +19,9 @@ class SPI:
                   firstbit=MSB, sck=None, mosi=None, miso=None):
         mode = 0
         if polarity:
-            mode |= CPOL
+            mode |= self.CPOL
         if phase:
-            mode |= CPHA
+            mode |= self.CPHA
 
         self.clock_pin = sck
         self.mosi_pin = mosi
@@ -30,9 +30,11 @@ class SPI:
         self.mode = mode
         self.bits = bits
 
-    def write(self, buf):
+    def write(self, buf, start=0, end=None):
         if not buf:
             return
+        if end is None:
+            end = len(buf)
         try:
             self._spi.open(self._port, 0)
             try:
@@ -42,15 +44,17 @@ class SPI:
             self._spi.max_speed_hz = self.baudrate
             self._spi.mode = self.mode
             self._spi.bits_per_word = self.bits
-            self._spi.writebytes([x for x in buf])
+            self._spi.writebytes([x for x in buf[start:end]])
             self._spi.close()
         except FileNotFoundError as not_found:
             print("Could not open SPI device - check if SPI is enabled in kernel!")
             raise
 
-    def readinto(self, buf):
+    def readinto(self, buf, start=0, end=None):
         if not buf:
             return
+        if end is None:
+            end = len(buf)
         try:
             self._spi.open(self._port, 0)
             try:
@@ -60,19 +64,24 @@ class SPI:
             self._spi.max_speed_hz = self.baudrate
             self._spi.mode = self.mode
             self._spi.bits_per_word = self.bits
-            data = self._spi.readbytes(len(buf))
-            for i in range(len(buf)):  # 'readinto' the given buffer
-              buf[i] = data[i]
+            data = self._spi.readbytes(end-start)
+            for i in range(end-start):  # 'readinto' the given buffer
+              buf[start+i] = data[i]
             self._spi.close()
         except FileNotFoundError as not_found:
             print("Could not open SPI device - check if SPI is enabled in kernel!")
             raise
 
-    def write_readinto(self, buffer_out, buffer_in, out_start=0, out_end=None, in_start=0, in_end=None):
+    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
+            raise RuntimeError('Buffer slices must be of equal length.')
         try:
             self._spi.open(self._port, 0)
             try:
@@ -82,10 +91,10 @@ class SPI:
             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))
-            for i in range(len(buffer_in)): # 'readinto' the given buffer
-                buffer_in[i] = data[i]
+            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
\ No newline at end of file
+            raise