From 275d988eccd1d8b3408ecf8aa39687c17d9278a5 Mon Sep 17 00:00:00 2001
From: Robin Krens <robin@robinkrens.nl>
Date: Sat, 10 Feb 2024 12:59:17 +0100
Subject: [PATCH] flasher.py: minor packet construct corrections

---
 flasher.py | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/flasher.py b/flasher.py
index 1ffe9ae..c388815 100644
--- a/flasher.py
+++ b/flasher.py
@@ -9,6 +9,9 @@ BAU_CMD = 0x34
 SIG_CMD = 0x3A
 ARE_CMD = 0x3B
 
+OK_READ_RES = 0x15
+OK_WRITE_RES = 0x13
+
 LOW_PULSE = 0x00
 GENERIC_CODE = 0x55
 BOOT_CODE = 0xC3
@@ -20,17 +23,17 @@ TESTID = [
     "0xCC", "0xCD", "0xCE", "0xCF"
 ]
 
-def calc_sum(data):
+def calc_sum(cmd, data):
     data_len = len(data)
     lnh = data_len + 1 & 0xFF00
     lnl = data_len + 1 & 0x00FF
-    res = lnh + lnl
+    res = lnh + lnl + cmd
     for i in range(data_len):
             if isinstance(data[i], str):
                 res += int(data[i], 16)
             else:
                 res += ord(data[i])
-    res = ~(res) & 0xFF # two's complement
+    res = ~(res - 1) & 0xFF # two's complement
     return (lnh, lnl, res)
 
 
@@ -44,42 +47,40 @@ def format_command(cmd, data):
     else:
         byte_data = bytes([int(x, 16) for x in data])
     
-    LNH, LNL, SUM = calc_sum(data)
+    LNH, LNL, SUM = calc_sum(int(cmd), data)
     ETX = 0x03
     fmt_header = '<BBBB'
     fmt_footer = 'BB'
-    print("sum calculation:", SUM)
     fmt = fmt_header + str(len(data)) + 's' + fmt_footer
-    print(fmt)
     pack = struct.pack(fmt, SOD, LNH, LNL, COM, byte_data, SUM, ETX)
-    print(pack)
+    print(fmt, pack, len(pack))
     return fmt
 
 # format of data packet is [SOD|LNH|LNL|RES|DAT|SUM|ETX]
-def format_data(data):
+def format_data(res, data):
     SOD = 0x81
     if (len(data) >= 1024):
         raise Exception(f'Data packet too large, data length is {DATA_LEN} (>1024)')
-    LNH, LNL, SUM = calc_sum(data)
+    LNH, LNL, SUM = calc_sum(int(res), data)
     DAT = bytes([int(x, 16) for x in data])
-    RES = 0x13
+    RES = res
     ETX = 0x03
     fmt_header = '<BBBB'
     fmt_footer = 'BB'
     fmt = fmt_header + str(len(data)) + 's' + fmt_footer
     pack = struct.pack(fmt, SOD, LNH, LNL, RES, DAT, SUM, ETX)
-    print(pack)
+    print(fmt, pack, len(pack))
 
 cmd = format_command(INQ_CMD, "")
-print(cmd, struct.calcsize(cmd))
 
 cmd = format_command(BAU_CMD, ['0x00','0x1E'])
-print(cmd, struct.calcsize(cmd))
 
 cmd = format_command(IDA_CMD, TESTID)
-print(cmd, struct.calcsize(cmd))
 
-format_data(['0x00','0x01','0x02'])
+format_data(0x13, ['0x00','0x01','0x02'])
+format_data(0x34, ['0x00'])
+format_data(0x00, ['0x00'])
+format_data(0x12, ['0x00'])
 
 
 
-- 
2.7.4