use bytes (integers) all along

Dealing with mixed integers and strings (or bytes() when pyserial decides to do so) is a PITA that plagues all the code with ord() conversions and makes it error-prone and hard to debug. It is even more so if the python version (2.7 or 3.x) is not known in advance. To play safe - the firmware file is converted at read time into a bytearray, which is what it is - all data flow that is supposed to come from/to the serial line is cast into integer values as soon/later as possible; given that pyserial gives back str/bytes somehow at will, ord() calls at the .recv() method level are the safest way to ensure we get-a-byte, get-a-byte, get-a-byte, byte, byte.

use bytes (integers) all along
Dealing with mixed integers and strings (or bytes() when pyserial decides to do so) is a PITA that plagues all the code with ord() conversions and makes it error-prone and hard to debug. It is even more so if the python version (2.7 or 3.x) is not known in advance. To play safe - the firmware file is converted at read time into a bytearray, which is what it is - all data flow that is supposed to come from/to the serial line is cast into integer values as soon/later as possible; given that pyserial gives back str/bytes somehow at will, ord() calls at the .recv() method level are the safest way to ensure we get-a-byte, get-a-byte, get-a-byte, byte, byte.
c117db54 · Juan David González Cobas · b6863a92 · c117db54
Commit c117db54 authored Dec 01, 2020 by Juan David González Cobas
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Showing with 21 additions and 20 deletions

usb-bootloader.py tools/uart-bootloader/usb-bootloader.py +21 -20

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--- a/tools/uart-bootloader/usb-bootloader.py
+++ b/tools/uart-bootloader/usb-bootloader.py
@@ -62,7 +62,7 @@ class SerialIF:
                if state == None or len(state) == 0:
                    continue
                #print ("************************ ST", state)
-                return state
+                return ord(state)
            except:
                #print("Sleep")
                time.sleep(1)
@@ -71,7 +71,7 @@ class SerialIF:
    def recv_nonblock(self):
        try:
            state = self.ser.read(1)
-            return state
+            return ord(state)
        except:
            return None

@@ -98,11 +98,11 @@ class SerialIF:
        frame = []

        while True:
-            b = ord(self.recv())
+            b = self.recv()
            if (b != 0x55):
                #    		sys.stderr.write("%c" % b)
                continue
-            b = ord(self.recv())
+            b = self.recv()
            if (b != 0xaa):
                #		sys.stderr.write("%c" % b)
                continue
@@ -110,17 +110,17 @@ class SerialIF:

        frame = [0x55, 0xaa]

-        rsp = ord(self.recv())
-        l = ord(self.recv())
+        rsp = self.recv()
+        l = self.recv()
        l <<= 8
-        l |= ord(self.recv())
+        l |= self.recv()

        for i in range(0, l):
-            frame.append(ord(self.recv()))
+            frame.append(self.recv())

-        crc = ord(self.recv())
+        crc = self.recv()
        crc <<= 8
-        crc |= ord(self.recv())
+        crc |= self.recv()

        return rsp

@@ -250,7 +250,7 @@ class DSIBootloader:
            n = 256 if remaining > 256 else remaining
            data = []
            for b in fw[p:p + n]:
-                data.append(ord(b))
+                data.append(b)

            #print("b0 %x" % data[0])

@@ -274,7 +274,7 @@ class DSIBootloader:
            n = 256 if remaining > 256 else remaining
            data = []
            for b in image[p:p + n]:
-                data.append(ord(b))
+                data.append(b)


 #	    print("addr %x l %d" %( p+addr, len(data)))
@@ -326,15 +326,16 @@ def run_terminal(ser):

    while True:
        a = ser.recv_nonblock()
-        if (a != None and len(a) > 0):
-            sys.stderr.write("%c" % a)
+        if (a != None):
+            sys.stderr.write(chr(a))
+            # flush is needed FIXME:
+            # sys.stderr.flush()

        a = os.read(sys.stdin.fileno(), 1)
-        if a != None and len(a) > 0:
-            if (ord(a) == 1):
-                return
-            else:
-                ser.send(ord(a))
+        if a and ord(a) == 1:
+            return      # exit on Ctrl-A
+        else:
+            ser.send(a)



@@ -378,7 +379,7 @@ def main(argv):
        sys.exit(2)

    boot = DSIBootloader(our_port)
-    fw = open(args[0], "rb").read()
+    fw = bytearray(open(args[0], "rb").read())

    boot.boot_enter()
    if do_flash: