gavrasm Gerd's AVR assembler version 2.6 (C)2010 by DG4FAC
----------------------------------------------------------
Source file: hello.ftdi.44.echo.asm
Hex file:    hello.ftdi.44.echo.hex
Eeprom file: hello.ftdi.44.echo.eep
Compiled:    17.10.2010, 17:06:16
Pass:        2
     1: ;
     2: ; hello.ftdi.echo.44.asm
     3: ;
     4: ; 115200 baud FTDI character echo
     5: ;
     6: ; Neil Gershenfeld
     7: ; 10/17/10
     8: ;
     9: ; (c) Massachusetts Institute of Technology 2010
    10: ; Permission granted for experimental and personal use;
    11: ; license for commercial sale available from MIT.
    12: ;
    13: 
    14: .include "tn44def.inc"
 -> Warning 009: Include defs not necessary, using internal values!
   File: hello.ftdi.44.echo.asm, Line: 14
   Source line: .include "tn44def.inc"
    15: 
    16: .equ rxpin = PA0; serial input pin
    17: .equ txpin = PA1; serial output pin
    18: .equ comm_port = PORTA; comm port
    19: .equ comm_dir = DDRA; comm direction
    20: .equ comm_pins = PINA; comm pins
    21: .def bitcnt = R16; bit counter
    22: .def temp = R17; temporary storage
    23: .def temp1 = R18; temporary storage
    24: .def txbyte = R19; transmit byte
    25: .def rxbyte = R20; receive byte
    26: 
    27: ;
    28: ; print
    29: ; 
    30: .macro print
    31:    ldi zl,low(@0*2)
    32:    ldi zh,high(@0*2)
    33:    rcall print_db
    34:    .endmacro
    35: 
    36: .cseg
    37: .org 0
    38: 000000   C028  rjmp reset
    39: 
    40: ;
    41: ; half_bit_delay
    42: ; serial half bit delay
    43: ;
    44: half_bit_delay:
    45: 000001   E119  ldi temp, 25; 115200 baud (20 MHz clock /1)
    46:    half_bit_delay_loop:
    47: 000002   951A  dec temp
    48: 000003   F7F1  brne half_bit_delay_loop
    49: 000004   9508  ret
    50: ;
    51: ; putchar
    52: ;    assumes line driver (inverts bits)
    53: ;
    54: putchar:
    55: 000005   E00A  ldi bitcnt, 10; 1 start + 8 data + 1 stop bit
    56: 000006   9530  com txbyte; invert everything
    57: 000007   9408  sec; set start bit
    58:    putchar0:
    59: 000008   F410  brcc putchar1; if carry set
    60: 000009   98D9  cbi comm_port, txpin; send a '0'
    61: 00000A   C002  rjmp putchar2; else	
    62:    putchar1:
    63: 00000B   9AD9  sbi comm_port, txpin	; send a '1'
    64: 00000C   0000  nop; even out timing
    65:    putchar2:
    66: 00000D   DFF3  rcall half_bit_delay; bit delay
    67: 00000E   DFF2  rcall half_bit_delay; " 
    68: 00000F   9536  lsr txbyte; get next bit
    69: 000010   950A  dec bitcnt; if not all bits sent
    70: 000011   F7B1  brne putchar0; send next bit
    71: 000012   9508  ret;
    72: ;
    73: ; getchar
    74: ;    assumes line driver (inverts bits)
    75: ;
    76: getchar:
    77: 000013   E009  ldi bitcnt, 9; 8 data + 1 stop bit
    78:    getchar1:
    79: 000014   99C8  sbic comm_pins, rxpin; wait for start bit
    80: 000015   CFFE  rjmp getchar1
    81: 000016   DFEA  rcall half_bit_delay; delay to middle of bit
    82:    getchar2:
    83: 000017   DFE9  rcall half_bit_delay; bit delay
    84: 000018   DFE8  rcall half_bit_delay; "
    85: 000019   9488  clc; clear carry
    86: 00001A   99C8  sbic comm_pins, rxpin; if RX pin low skip
    87: 00001B   9408  sec; otherwise set carry
    88: 00001C   950A  dec bitcnt
    89: 00001D   F011  breq getchar3; return if all bits read
    90: 00001E   9547  ror rxbyte; otherwise shift bit into receive byte
    91: 00001F   CFF7  rjmp getchar2; go get next bit
    92:    getchar3:
    93: 000020   9508  ret
    94: ;
    95: ; print_db
    96: ; prints a null-terminated .db string
    97: ;
    98: print_db:
    99:    print_loop:
   100: 000021   95C8  lpm
   101: 000022   2D30  mov txbyte,R0
   102: 000023   3030  cpi txbyte,0
   103: 000024   F019  breq return
   104: 000025   DFDF  rcall putchar
   105: 000026   9631  adiw zl, 1
   106: 000027   CFF9  rjmp print_loop
   107:    return:
   108: 000028   9508  ret
   109: ;
   110: ; main program
   111: ;
   112: reset:
   113:    ;
   114:    ; set fuse low byte to 0x7E for 20 MHz resonator
   115:    ;
   116:    ; set clock divider to /1
   117:    ;
   118: 000029   E810  ldi temp, (1 << CLKPCE)
   119: 00002A   E020  ldi temp1, (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0)
   120: 00002B   BD16  out CLKPR, temp
   121: 00002C   BD26  out CLKPR, temp1
   122:    ;
   123:    ; set stack pointer to top of RAM
   124:    ;
   125: 00002D   E011  ldi temp, high(RAMEND)
   126: 00002E   BF1E  out SPH, temp
   127: 00002F   E51F  ldi temp, low(RAMEND)
   128: 000030   BF1D  out SPL, temp
   129:    ;
   130:    ; init comm pin
   131:    ;
   132: 000031   9AD9  sbi comm_port, txpin
   133: 000032   9AD1  sbi comm_dir, txpin
   134:    ;
   135:    ; start main loop
   136:    ;
   137:    loop:
   138: 000033   DFDF  rcall getchar
   139:       print message
   140:          message: .db "hello.ftdi.44.echo.asm: you typed ",0
 -> Warning 004: Number of bytes on line is odd, added 00 to fit program memory!
   File: hello.ftdi.44.echo.asm, Line: 140
   Source line:          message: .db "hello.ftdi.44.echo.asm: you typed ",0
        000037 6568 6C6C 2E6F 7466
        00003B 6964 342E 2E34 6365
        00003F 6F68 612E 6D73 203A
        000043 6F79 2075 7974 6570
        000047 2064 0000
   141: 000049   2F34  mov txbyte, rxbyte
   142: 00004A   DFBA  rcall putchar
   143: 00004B   E03A  ldi txbyte,10
   144: 00004C   DFB8  rcall putchar
   145: 00004D   CFE5  rjmp loop

Program             :       60 words.
Constants           :       18 words.
Total program memory:       78 words.
Eeprom space        :        0 bytes.
Data segment        :        0 bytes.
Compilation completed, no errors.
Compilation endet 17.10.2010, 17:06:16