stc8: print additional MCU info

Print manufacturing date as well as the factory-measured internal
voltage reference value. These values are displayed by STC-ISP, too.

doc/stc8-protocol.txt

@@ -20,7 +20,8 @@ Status packet
 -------------
 
 46 B9 68 00 30   50 00 54 62 58 5D 00 04 FF FD 8B BF FF 27 4A F7 FE 73 55 00 F6 28 09 85 E3 5F 80 07 20 20 20 01 00 00 FE 05 3A 17 05 25 91 FF   10 AE 16
-                                                                                      ^^^^^ wakeup clock
+                                                                                      ^^^^^ wakeup clock                  ^^^^^ reference voltage
+                                                                                                                                ^^^^^^^^ mfg. date
 
 Clock set to 20 MHz by STC-ISP (encoding is different compared to STC15):
 

stcgal/protocols.py

@@ -1554,6 +1554,8 @@ class Stc8Protocol(Stc15Protocol):
     def __init__(self, port, handshake, baud, trim):
         Stc15Protocol.__init__(self, port, handshake, baud, trim)
         self.trim_divider = None
+        self.reference_voltage = None
+        self.mfg_date = ()
 
     def initialize_options(self, status_packet):
         """Initialize options"""
@@ -1580,6 +1582,12 @@ class Stc8Protocol(Stc15Protocol):
 
         # wakeup timer factory value
         self.wakeup_freq, = struct.unpack(">H", packet[23:25])
+        self.reference_voltage, = struct.unpack(">H", packet[35:37])
+        self.mfg_date = (
+            2000 + Utils.decode_packed_bcd(packet[37]),
+            Utils.decode_packed_bcd(packet[38]),
+            Utils.decode_packed_bcd(packet[39])
+        )
 
         bl_version, bl_stepping = struct.unpack("BB", packet[17:19])
         bl_minor = packet[22] & 0x0f
@@ -1587,6 +1595,12 @@ class Stc8Protocol(Stc15Protocol):
                                                bl_minor, chr(bl_stepping))
         self.bsl_version = bl_version
 
+    def print_mcu_info(self):
+        """Print additional STC8 info"""
+        super().print_mcu_info()
+        print("Target ref. voltage: %d mV" % self.reference_voltage)
+        print("Target mfg. date: %04d-%02d-%02d" % self.mfg_date)
+
     def calibrate(self):
         """Calibrate selected user frequency frequency and switch to selected baudrate."""
 

stcgal/utils.py

@@ -52,6 +52,11 @@ class Utils:
 
         return sep.join(["%02X" % x for x in bytes(bytestr)])
 
+    @classmethod
+    def decode_packed_bcd(cls, byt):
+        """Decode two-digit packed BCD value"""
+        return (byt & 0x0f) + (10 * (byt >> 4))
+
 
 class BaudType:
     """Check baud rate for validity"""

tests/test_utils.py

@@ -64,6 +64,14 @@ class TestUtils(unittest.TestCase):
         with self.assertRaises(Exception):
             Utils.hexstr([400, 500])
 
+    def test_decode_packed_bcd(self):
+        """Test packed BCD decoder"""
+        self.assertEqual(Utils.decode_packed_bcd(0x01), 1)
+        self.assertEqual(Utils.decode_packed_bcd(0x10), 10)
+        self.assertEqual(Utils.decode_packed_bcd(0x11), 11)
+        self.assertEqual(Utils.decode_packed_bcd(0x25), 25)
+        self.assertEqual(Utils.decode_packed_bcd(0x99), 99)
+
 class TestBaudType(unittest.TestCase):
     """Test BaudType class"""