flasher.py: initial unpacking

diff --git a/flasher/flasher.py b/flasher/flasher.py
index c388815..055bce3 100644 (file)
--- a/flasher/flasher.py
+++ b/flasher/flasher.py
@@ -1,5 +1,23 @@
+# Copyright (C) Robin Krens - 2024
+# 
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+#
+
 import struct
 
+# Commands send to boot firmware
 INQ_CMD = 0x00
 ERA_CMD = 0x12
 WRI_CMD = 0x13
@@ -9,9 +27,27 @@ BAU_CMD = 0x34
 SIG_CMD = 0x3A
 ARE_CMD = 0x3B
 
-OK_READ_RES = 0x15
-OK_WRITE_RES = 0x13
-
+# These are combined with send command, for example
+# STATUS_OK | ERA_CMD == 0x12
+# STATUS_ERR | ERA_CMD = 0x92
+STATUS_OK = 0x00
+STATUS_ERR = 0x80
+
+# Error codes
+ERR_UNSU = 0xC
+ERR_PCKT = 0xC1
+ERR_CHKS = 0xC2
+ERR_FLOW = 0xC3
+ERR_ADDR = 0xD0
+ERR_BAUD = 0xD4
+ERR_PROT = 0xDA
+ERR_ID = 0xDB
+ERR_SERI = 0xDC
+ERR_ERA = 0xE1
+ERR_WRI = 0xE2
+ERR_SEQ = 0xE7
+
+# used for init sequence
 LOW_PULSE = 0x00
 GENERIC_CODE = 0x55
 BOOT_CODE = 0xC3
@@ -71,10 +107,32 @@ def format_data(res, data):
     pack = struct.pack(fmt, SOD, LNH, LNL, RES, DAT, SUM, ETX)
     print(fmt, pack, len(pack))
 
-cmd = format_command(INQ_CMD, "")
+# packet received from mcu 
+def unpack_header(data):
+    header = data[0:4]
+    fmt_header = '<BBBB'
+    SOD, LNH, LNL, RES = struct.unpack(fmt_header, header)
+    if (SOD != 0x81):
+        raise Exception(f'Wrong start of packet data received')
+    pkt_len = (LNH << 0x8 | LNL) - 1
+    if (RES & 0x80):
+        raise Exception(f'MCU encountered error {RES & 0x7F}')
+    fmt_message = '<' + str(pkt_len) + 's'
+    raw = struct.unpack_from(fmt_message, data, 4)[0]
+    message = ['0x{:02X}'.format(byte) for byte in raw]
+    fmt_footer = '<BB'
+    SUM, ETX = struct.unpack_from(fmt_footer, data, 4 + pkt_len)
+    lnh, lnl, local_sum = calc_sum(RES, message)
+    if (SUM != local_sum):
+        raise Exception(f'Sum calculation mismatch, read {local_sum} instead of {SUM}')
+    if (ETX != 0x03):
+        raise Exception(f'Packet ETX error')
+    return message
 
-cmd = format_command(BAU_CMD, ['0x00','0x1E'])
+    
 
+cmd = format_command(INQ_CMD, "")
+cmd = format_command(BAU_CMD, ['0x00','0x1E'])
 cmd = format_command(IDA_CMD, TESTID)
 
 format_data(0x13, ['0x00','0x01','0x02'])
@@ -82,5 +140,6 @@ format_data(0x34, ['0x00'])
 format_data(0x00, ['0x00'])
 format_data(0x12, ['0x00'])
 
-
-
+#print(unpack_header(b'\x81\x00\x02\x08\xC0\x12\x03'))
+#print(unpack_header(b'\x81\x00\x03\x08\xC0\xD0\x12\x03'))
+print(unpack_header(b'\x81\x00\x02\x00\x00\xFE\x03'))