Working ADB transfer at very low speeds (adding a delay in python terminal)

assembly/os/drivers/arduino_terminal.asm

@@ -61,17 +61,14 @@ Term_readline:
     ld bc, incoming_string  ; Returns read string pointer
     ret
 
-; Returns the number of bytes available on the parallel port using the 
-; DATA_AVAILABLE register.
-; @return a the number of available bytes
-Term_availb:
-    in a, (TERM_DATA_AVAIL_REG)
-    ret
-
 ; Reads the first available byte on the serial port using the DATA register.
+; Waits for the Terminal DATA_AVAILABLE register to be non-zero before reading.
 ; 0s are not ignored (cannot be used with keyboard)
 ; Affects NO condition bits!
 ; @return the available byte, even if 0
 Term_readb:
+    in a, (TERM_DATA_AVAIL_REG)
+    cp 0
+    jp z, Term_readb
     in a, (TERM_DATA_REG)    ; reads a byte
     ret

assembly/os/monitor.asm

@@ -274,8 +274,8 @@ monitor_adb:
     ; start copying incoming data to application space
     call monitor_copyTermToAppMem
     ;jp APP_SPACE    ; Start executing code
-    ld bc, APP_SPACE
+    ; ld bc, APP_SPACE
-    call Sys_Print
+    ; call Sys_Print
     jp monitor_main_loop
 
 ; Prints "0x" and read 1 hex byte (2 hex digits, e.g. 0x8C)
@@ -482,11 +482,6 @@ monitor_copyTermToAppMem:
     ld d, 2
     ld hl, APP_SPACE    ; we will write in APP_SPACE
     monitor_copyTermToAppMem_loop:
-        ; check if bytes are available
-        call Term_availb
-        cp 0
-        jp z, monitor_copyTermToAppMem     ; no bytes available, next loop
-        ; bytes are available
         ld a, d
         cp 2    ; check if we are receiving first header byte
         jp z, monitor_copyTermToAppMem_loop_rec_head_byte_1
@@ -494,20 +489,29 @@ monitor_copyTermToAppMem:
         cp 1    ; check if we are receiving second header byte
         jp z, monitor_copyTermToAppMem_loop_rec_head_byte_2
         ; we are receiving binary stream: read byte and save to memory
-        call Term_readb
+        call Term_readb ; reads a byte from terminal
         ld (hl), a  ; copy byte to memory
         inc hl  ; move to next memory position
-    jp monitor_copyTermToAppMem_loop   ; continue loop
+        dec bc  ; decrement remaining bytes counter
+        ; check if we reached the number of bytes to be transferred
+        ld a, b
+        cp 0
+        jp nz, monitor_copyTermToAppMem_loop   ; continue loop
+        ld a, c
+        cp 0
+        jp nz, monitor_copyTermToAppMem_loop   ; continue loop
+        ; all bytes received, return
+        ret
 
     monitor_copyTermToAppMem_loop_rec_head_byte_1:
         ; we are receiving first header byte: read byte and save to b
-        call Term_readb
+        call Term_readb ; reads a byte from terminal
         ld b, a
         dec d
         jp monitor_copyTermToAppMem_loop   ; continue loop
     monitor_copyTermToAppMem_loop_rec_head_byte_2:
         ; we are receiving second header byte: read byte and save to c
-        call Term_readb
+        call Term_readb ; reads a byte from terminal
         ld c, a
         dec d
         jp monitor_copyTermToAppMem_loop   ; continue loop

python/terminal_emulator.py

@@ -31,10 +31,13 @@ import os
 
 
 class TerminalEmulator:
+    SYNC_SLEEP = 0.001
+
     def __init__(self, w, ser):
         w.clear()
         w.move(0,0)
         while True:
+
             # read serial port and write to curses
             if ser.inWaiting():
                 b = ser.read(1)
@@ -45,6 +48,7 @@ class TerminalEmulator:
             key = w.getch()
             if key == 10 or (key > 31 and key < 256):
                 # Is a character
+                time.sleep(self.SYNC_SLEEP)
                 ser.write(bytes([key]))
             elif int(key) == 1:     # CTRL+A, enter ADB mode
                 # Save cursor position
@@ -67,20 +71,29 @@ class TerminalEmulator:
         w.addstr(0, 0, '[ADB MODE] file to load:', curses.A_REVERSE)
         path = w.getstr()
         try:
+            header = bytearray(2)
             size = os.path.getsize(path)
             # Compute the two header bytes needed to declare the length of the stream
-            h1 = size & 255 # get lower 8 bits
+            header[1] = size & 255 # get lower 8 bits
             size >>= 8 # shift by 8 bits
-            h0 = size & 255 # get second lower 8 bits
+            header[0] = size & 255 # get second lower 8 bits
+            # Log size for debug
+            w.addstr("Header bytes: {}".format(header.hex()))
+            w.refresh()
+
             # Send the two heading bytes (most significant first)
-            ser.write(h0)
+            ser.write(header[0:1])
-            ser.write(h1)
+            time.sleep(self.SYNC_SLEEP)
+            ser.write(header[1:2])
+            time.sleep(self.SYNC_SLEEP)
+
             # Send the actual binary stream
             with open(path, "rb") as f:
                 byte = f.read(1)
                 while byte:
                     ser.write(byte)
                     byte = f.read(1)
+                    time.sleep(self.SYNC_SLEEP)
         except IOError as e:
             w.move(0,0)
             w.clrtoeol()