Add first working communication with the DAB752

1 files changed, 204 insertions, 0 deletions

diff --git a/dab752.py b/dab752.py
new file mode 100644
index 0000000..c7bbb1b
--- /dev/null
+++ b/dab752.py
@@ -0,0 +1,204 @@
+#!/usr/bin/env python
+
+import sys
+import serial
+
+PACKETRETRY = 3
+MAXDATLEN = 128
+CRCPOLY = 0x810
+CRCINIT = 0xFFFF
+
+TX_ACKTIMEOUT = 3 #sec
+RX_BYTETIMEOUT = 1 #sec
+
+STX_header = 0x02
+SOH_header = 0x01
+ETB_header = 0x17
+ETX_header = 0x03
+ACK_header = 0x06
+NAK_header = 0x15
+
+def crc_initial(c):
+    crc = 0
+    c = c << 8
+    for j in range(8):
+        if (crc ^ c) & 0x8000:
+            crc = (crc << 1) ^ CRCPOLY
+        else:
+            crc = crc << 1
+        c = c << 1
+        crc = crc & 0xFFFF
+    return crc
+
+crc_table = [ crc_initial(i) for i in range(256) ]
+
+def get_crc(data):
+    crc = 0
+    for d in data + [0xff, 0xff]:
+        if d < 0 or d > 255:
+            raise ValueError("data value out of bounds")
+        crc_h = crc >> 8
+        crc   = ((crc << 8) | d) & 0xFFFF
+        crc   = crc ^ crc_table[crc_h]
+    return [crc >> 8, crc & 0xff]
+
+def check_crc(data):
+    return get_crc(data[:-2]) == data[-2:]
+
+class LLCP:
+    def __init__(self, port):
+        self.packet_id = 0
+        self.serial = serial.Serial(port, 19200, timeout=0.5)
+
+    def _tx_data(self, data):
+        print("TX %r" % data)
+
+        self.serial.write(data)
+
+        self.receive_packet()
+
+    def receive_packet(self):
+        packet = []
+
+        header = self.serial.read()
+        if not header:
+            print("RX timeout")
+            return []
+        header = ord(header)
+        packet.append(header)
+
+        if header == SOH_header or \
+           header == STX_header or \
+           header == ETB_header or \
+           header == ETX_header or \
+           header == ACK_header or \
+           header == NAK_header:
+            packet_id = self.serial.read()
+            if not packet_id:
+                print("packet_id timeout")
+                return []
+            packet_id = ord(packet_id)
+            packet.append(packet_id)
+
+            if header != ACK_header and header != NAK_header:
+                length = self.serial.read()
+                if not length:
+                    print("length timeout")
+                    return []
+                length = ord(length)
+                if length > MAXDATLEN:
+                    print("length invalid")
+                    return []
+                packet.append(length)
+
+                data = self.serial.read(length)
+                if len(data) < length:
+                    print("data length too short")
+                    return []
+                packet.extend(data)
+
+            crch, crcl = self.serial.read(2)
+            if not crch or not crcl:
+                print("crc timeout")
+                return []
+            packet.append(crch)
+            packet.append(crcl)
+
+            if header == SOH_header:
+                print("SOH")
+            if header == STX_header:
+                print("STX")
+            if header == ETB_header:
+                print("ETB")
+            if header == ETX_header:
+                print("ETX")
+            if header == ACK_header:
+                print("ACK")
+            if header == NAK_header:
+                print("NAK")
+
+            if check_crc(packet):
+                print("RX CRC Valid")
+
+                if header != ACK_header and header != NAK_header:
+                    print("Send ACK")
+                    ack_data = [ACK_header, packet_id]
+                    ack_data.extend(get_crc(ack_data))
+                    self._tx_data(ack_data)
+            else:
+                print("RX CRC INVALID")
+
+                if header != ACK_header and header != NAK_header:
+                    print("Send NAK")
+                    ack_data = [NAK_header, packet_id]
+                    ack_data.extend(get_crc(ack_data))
+                    self._tx_data(ack_data)
+
+            print("RX %r" % packet)
+            return packet
+
+
+
+    def transmit(self, message):
+        self.packet_id += 1
+        data = []
+        if len(message) < MAXDATLEN:
+            data.append(STX_header)
+            data.append(self.packet_id)
+            data.append(len(message))
+            data.extend(message)
+            data.extend(get_crc(data))
+            self._tx_data(data)
+        else:
+            h = SOH_header
+            sent_bytes = 0
+            while sent_bytes < len(message):
+                message_part = message[sent_bytes:sent_bytes+MAXDATLEN]
+
+                data.append(h)
+                data.append(self.packet_id)
+                data.append(len(message_part))
+                data.extend(message_part)
+                data.extend(get_crc(data))
+
+                self._tx_data(data)
+
+                sent_bytes += len(message_part)
+                h = ETB_header
+                if len(message) - sent_bytes < MAXDATLEN:
+                    h = ETX_header
+
+llcp = LLCP("/dev/ttyUSB0")
+
+LnkRegister = 129
+GetComponentList = 39
+GetCurrentFrequency = 41
+
+# Send a Link Register On message
+print("Send a LnkRegister")
+for i in range(4):
+    llcp.transmit([LnkRegister, 1])
+    rx = llcp.receive_packet()
+    print()
+    if rx:
+        break
+
+print("Send invalid opcode")
+llcp.transmit([78])
+llcp.receive_packet()
+print()
+
+print("Send GetComponentList")
+llcp.transmit([GetComponentList])
+llcp.receive_packet()
+print()
+
+print("Send GetCurrentFrequency")
+llcp.transmit([GetCurrentFrequency])
+llcp.receive_packet()
+print()
+
+print("Send a LnkRegister Off")
+llcp.transmit([LnkRegister, 0])
+llcp.receive_packet()
+print()