From 5542a152492a959f6be72a4034c90f4191d70f7b Mon Sep 17 00:00:00 2001
From: ladyada <limor@ladyada.net>
Date: Sat, 25 Aug 2018 00:18:08 -0400
Subject: [PATCH] SPI working

---
 adafruit_pn532.py | 63 +++++++++++++++++++++++++++++++++++++++++++++--
 examples/main.py  | 22 ++---------------
 2 files changed, 63 insertions(+), 22 deletions(-)

diff --git a/adafruit_pn532.py b/adafruit_pn532.py
index 9d45ced..8994d13 100644
--- a/adafruit_pn532.py
+++ b/adafruit_pn532.py
@@ -144,6 +144,16 @@ _GPIO_P35                      = const(5)
 _ACK                           = b'\x00\x00\xFF\x00\xFF\x00'
 _FRAME_START                   = b'\x00\x00\xFF'
 
+def reverse_bit(num):
+    result = 0
+    for _ in range(8):
+        result <<= 1
+        result += (num & 1)
+        num >>= 1
+    return result
+
+
+
 class BusyError(Exception):
     """Base class for exceptions in this module."""
     pass
@@ -156,7 +166,6 @@ class PN532:
         """
         self.debug = debug
         if reset:
-            print("resetting")
             reset.direction = Direction.OUTPUT
             reset.value = True
             time.sleep(0.1)
@@ -408,7 +417,7 @@ class PN532_I2C(PN532):
                         return True
                     else:
                         time.sleep(0.1)
-        return True
+        return False
 
     def _read_data(self, count):
         """Read a specified count of bytes from the PN532."""
@@ -426,3 +435,53 @@ class PN532_I2C(PN532):
     def _write_data(self, framebytes):
         with self._i2c:
             self._i2c.write(framebytes)
+
+class PN532_SPI(PN532):
+    """Driver for the PN532 connected over I2C."""
+    def __init__(self, spi, cs_pin, *, irq=None, reset=None, debug=False):
+        """Create an instance of the PN532 class using SPI
+        """
+        self.debug = debug
+        self._irq = irq
+        self._spi = spi_device.SPIDevice(spi, cs_pin)
+        super().__init__(debug=debug, reset=reset)
+
+    def _wait_ready(self, timeout=1):
+        if self._irq:
+            print("TODO IRQ")
+        else:
+            status = bytearray([reverse_bit(_SPI_STATREAD), 0])
+
+            t = time.monotonic()
+            while (time.monotonic() - t) < timeout:
+                with self._spi as spi:
+                    spi.write_readinto(status, status)
+                if reverse_bit(status[1]) == 0x01:  # LSB data is read in MSB
+                    return True
+                else:
+                    time.sleep(0.1)
+        return False
+
+    def _read_data(self, count):
+        """Read a specified count of bytes from the PN532."""
+        # Build a read request frame.
+        frame = bytearray(count+1)
+        # Add the SPI data read signal byte, but LSB'ify it
+        frame[0] = reverse_bit(_SPI_DATAREAD)
+        
+        with self._spi as spi:
+            time.sleep(0.01)
+            spi.write_readinto(frame, frame)
+            for i in range(len(frame)):
+                frame[i] = reverse_bit(frame[i]) # turn LSB data to MSB
+        if self.debug:
+            print("Reading: ", [hex(i) for i in frame[1:]])
+        return frame[1:]
+
+    def _write_data(self, framebytes):
+        with self._spi as spi:
+            reversed = [reverse_bit(x) for x in bytes([_SPI_DATAWRITE]) + framebytes]
+            time.sleep(0.01)
+            if self.debug:
+                print("writing: ", [hex(i) for i in reversed])
+            spi.write(bytes(reversed))
diff --git a/examples/main.py b/examples/main.py
index ab0adf6..3c57423 100644
--- a/examples/main.py
+++ b/examples/main.py
@@ -1,23 +1,5 @@
-from Adafruit_Circuitpython_PN532 import adafruit_pn532
-from digitalio import DigitalInOut, Direction, Pull
-import board
-import time
-import busio
-# I2C connection:
-i2c = busio.I2C(board.SCL, board.SDA)
-pn532 = adafruit_pn532.PN532_I2C(i2c)
-
-ic, ver, rev, support = pn532.get_firmware_version()
-print('Found PN532 with firmware version: {0}.{1}'.format(ver, rev))
-
-# Configure PN532 to communicate with MiFare cards.
-pn532.SAM_configuration()
-
-print('Waiting for MiFare card...')
-while True:
-    # Check if a card is available to read
-    uid = pn532.read_passive_target(timeout=0.25)
+ush=True)
     # Try again if no card is available.
     if uid is None:
         continue
-    print('Found card with UID:', [hex(i) for i in uid])
\ No newline at end of file
+    print('Found card with UID:', [hex(i) for i in uid])