Fix/22 io error long cmds (#23)

* feat: Add function for parsing the firmware version info into a named tuple.

* fix: Fix io errors due to driver not polling ACK frame correctly. Fixes #22

Long commands do not ack immediately so we are supposed to poll for the ack frame. quick2wire throws an error if the read is not acked though so we need to catch those errors and poll again after a brief wait. If we timeout we return an error code instead of raising an exception.

* doc: Update README to indicate using the 5v pin on the raspberry pi is safe.
Bump version minor.
Correct email in packaging step.

README.md

@@ -41,9 +41,9 @@ This is a port of [Seeed Studios's PN532 Arduino Library](https://github.com/See
 
 ## Power
 The Raspberry Pi 3.3v regulator does not provide enough current to drive the PN532 chip. 
-If you try to run the PN532 off your Raspberry Pi it will reset randomly and may not respond to commands.
-Instead you will need another power source (3.3v) to power the PN532. Some people have been able to run 
-the PN532 off of the 5V rail of the raspberry pi but this is not the recommended way of powering it.
+If you try to run the PN532 off your Raspberry Pi 3.3v it will reset randomly and may not respond to commands.
+Instead you will need another power source (3.3v or 5v) to power the PN532. It is generally safe to tap into the
+5v pin on the Raspberry Pi so long as your power supply can provide enough power for the PN532 and the pi.
 
 ## I2C Interface
 

pn532pi/interfaces/pn532i2c.py

@@ -2,6 +2,7 @@
 
 from pn532pi.nfc.pn532_log import DMSG
 from quick2wire.i2c import I2CMaster, writing, reading
+import errno
 
 from pn532pi.interfaces.pn532Interface import Pn532Interface, PN532_PREAMBLE, PN532_STARTCODE1, PN532_STARTCODE2, PN532_HOSTTOPN532, \
     PN532_INVALID_FRAME, PN532_POSTAMBLE, PN532_PN532TOHOST, PN532_ACK_WAIT_TIME, PN532_TIMEOUT, \
@@ -154,18 +155,24 @@ def _readAckFrame(self) -> int:
         DMSG('\n')
 
         t = 0
-        while 1:
-            responses = self._wire.transaction(reading(PN532_I2C_ADDRESS, len(PN532_ACK) + 1))
-            data = bytearray(responses[0])
-            if (data[0] & 1):
-              # check first byte --- status
-                break # PN532 is ready
-
+        while t <= PN532_ACK_WAIT_TIME:
+            try:
+                responses = self._wire.transaction(reading(PN532_I2C_ADDRESS, len(PN532_ACK) + 1))
+                data = bytearray(responses[0])
+                if (data[0] & 1):
+                    # check first byte --- status
+                    break # PN532 is ready
+            except IOError as e:
+                # As of Python 3.3 IOError is the same as OSError so we should check the error code
+                if e.errno != errno.EIO:
+                    raise   # Reraise the error   
+                # Otherwise do nothing, sleep and try again
+
             time.sleep(.001)    # sleep 1 ms
             t+=1
-            if (t > PN532_ACK_WAIT_TIME):
-                DMSG("Time out when waiting for ACK\n")
-                return PN532_TIMEOUT
+        else:
+            DMSG("Time out when waiting for ACK\n")
+            return PN532_TIMEOUT
 
         DMSG("ready at : ")
         DMSG(time.time())

pn532pi/nfc/pn532.py

@@ -4,7 +4,7 @@
     @license  BSD
 
 """
-from typing import List
+from typing import List, NamedTuple
 
 from pn532pi.interfaces.pn532Interface import Pn532Interface, PN532_TIMEOUT
 
@@ -126,6 +126,33 @@
 FELICA_WRITE_MAX_BLOCK_NUM          = 10 # for typical FeliCa card
 FELICA_REQ_SERVICE_MAX_NODE_NUM     = 32
 
+# Support options in FW Version Info
+SUPPORTS_ISO18092 = 0b100
+SUPPORTS_ISO14443_A = 0b010
+SUPPORTS_ISO14443_B = 0b001
+class Pn532FirmwareInfo(NamedTuple):
+    """
+    Information contained in the response to the 
+    GetFirmwareVersion command
+    """
+    ic_version: int
+    fw_major: int
+    fw_minor: int
+    support_opts: int
+    iso18092: bool
+    iso14443_a: bool
+    iso14443_b: bool
+
+    def __str__(self) -> str:
+        all_opts = [('ISO18092', self.iso18092), ('ISO4443-A', self.iso14443_a), 
+                    ('ISO4443-B', self.iso14443_b)]
+        opts = [name for name, supported in all_opts if supported]
+        return (f'Pn532FirmwareInfo(IC Version: {hex(self.ic_version)}, '
+                f'FW Version: {self.fw_major}.{self.fw_minor}, '
+                f'Supports: {opts} ({hex(self.support_opts)}))')
+
+    def __repr__(self) -> str:
+        return str(self)
 
 class Pn532:
     def __init__(self, interface: Pn532Interface):
@@ -149,6 +176,8 @@ def getFirmwareVersion(self) -> int:
         """
         Checks the firmware version of the PN5xx chip
 
+        See https://www.nxp.com/docs/en/user-guide/141520.pdf page 73
+
         :returns:  The chip's firmware version and ID
         """
         if (self._interface.writeCommand(bytearray([PN532_COMMAND_GETFIRMWAREVERSION]))):
@@ -168,6 +197,20 @@ def getFirmwareVersion(self) -> int:
         # response |= self.pn532_packetbuffer[3]
 
         return int.from_bytes(response, byteorder='big')
+
+    def getFirmwareInfo(self) -> tuple:
+        """
+        Parse the firmware version info into its separate parts
+        Format: |ic_version[8] | fw_version[8] | fw_revision[8] | support_opts[8]|
+        """
+        firmware_data = self.getFirmwareVersion()
+        opts, fw_min, fw_maj, ic_ver = [(firmware_data >> i) & 0xFF for i in range(0, 32, 8)]
+
+        return Pn532FirmwareInfo(ic_ver, fw_maj, fw_min, opts, 
+                                 bool(opts & SUPPORTS_ISO18092), 
+                                 bool(opts & SUPPORTS_ISO14443_A),
+                                 bool(opts & SUPPORTS_ISO14443_B))
+
 
     def readRegister(self, reg: int) -> int:
         """

setup.py

@@ -5,9 +5,9 @@
 
 setuptools.setup(
     name="pn532pi",
-    version="1.6",
+    version="1.7",
     author="gassajor000",
-    author_email="lgassjsg@example.com",
+    author_email="[email protected].com",
     description="PN532 library for Raspberry Pi",
     long_description=long_description,
     long_description_content_type="text/markdown",