HELP 74LV8153N Shitft register ,can anyone give me code ???

Igor_Rast

Hi there , ive been fooling around some time to get this 74lv8153 shift register working over 1 wire so I can save some pin's.
thout I had a working program but i lost it and it didn't work well

can anyone please help me with some sample code on how to get the
data in the shift register,

2start bit+ 3 Adress bits + 4 data bits + 1stop bit
sending this string twice should get the data in but i can't get it working right

please some help ,
if the codet can read let say from a data file how to set the outputstates would be great *** thats what I finally need, or just a good control of the shift register

hope to hear something
igor

Sapieha

Hi.

As it is standard RS232 serial to parallel.
You can use any of Serial RS232 driver in OBX

Igor_Rast wrote: »

Hi there , ive been fooling around some time to get this 74lv8153 shift register working over 1 wire so I can save some pin's.
thout I had a working program but i lost it and it didn't work well

can anyone please help me with some sample code on how to get the
data in the shift register,

2start bit+ 3 Adress bits + 4 data bits + 1stop bit
sending this string twice should get the data in but i can't get it working right

please some help ,
if the codet can read let say from a data file how to set the outputstates would be great *** thats what I finally need, or just a good control of the shift register

hope to hear something
igor

Cluso99

Remember, the serial is really 1 start bit plus the first data bit=1 (the docs say 2 start bits, first 0 then 1, which is a little confusing to those who really do not know much about serial).

Ariba

You can change the TX methode of the Simple_Serial a bit to output 20 bits. This needs no additional cog, and allows baudrates up to ~19.2 kBaud.

Here is apossible send methode (untested):

CON
  TxPin   = 0      ' set your out pin here
  BitTime = 80_000_000 / 19200
  
PUB Send(addr,value) : txByte | t

  txByte := %11_0000_000_10_1_0000_000_10    ' set start-stop bits
  txByte |= addr<<2 | addr<< 12       ' add address (0..7)
  txByte |= (value & $0F) << 5        ' add low nibble 
  txByte |= (value & $F0) << 11       ' add high nibble
  t := cnt                            ' sync
  repeat 21                           ' 20 bits in total + stop
    waitcnt(t += BitTime)             ' wait bit time
    outa[TxPin] := (txByte >>= 1)     ' output bits  

Andy

Cluso99

Perhaps I did not make my reply clear. You can use any of the serial drivers without modification. You just send two 8bit bytes as the serial driver normally would.

Serial data sends the low bit first (immediately after the start bit). The protocol of the 74xx8153 requires 2 start bits, 7 data bits and 1 stop bits, two characters. However, the 2 start bits is a misnomer because they require the second start bit to be a "1" not a "0". Therefore, what they really mean is 1 start bit "0" followed by the lowest bit (must always be "1") followed by a0, a1, a2 as the address bits (determined by the hardware pins), followed by d0, d1, d2, d3 of the low nibble of the latch contents you require to set, followed by a stop bit ("1"). The next character is start "0" followed by a "1" followed by a0, a1, a2 again, and then data bits d4, d5, d6, d7 of the high nibble of the latch contents you require to set and stop bit..

So, your 2 characters (bytes) to be sent are...
%d3, d2, d1, d0, a2, a1, a0, "1"
%d7, d6, d5, d4, a2, a1, a0, "1"

I hope this makes sense.
The first byte is made up of %1aaallll where aaa=the address pins, and llll (LLLL) = low nibble. The second byte is %1aaauuu where uuuu = the upper nibble. Configure to send at 24,000 baud or less (19,200 would be a good choice).

Igor_Rast

thnx for your reply's but im trying your pice of code but can't get it working

i did somthing like this

CON
  TxPin   = 23      ' set your out pin here
  BitTime = 80_000_000 / 19200
   _clkmode = xtal1 + pll16x
   _xinfreq = 5_000_000
 
OBJ

  ss : "simple_serial"
   
PUB main                 : txByte | t 

    dira[23]~~
    outa[23]~~
    
    
  repeat
      send(000,%01010101)
      



PUB Send(addr,value) : txByte | t

  txByte := %11_0000_000_10_1_0000_000_10    ' set start-stop bits
  txByte |= addr<<2 | addr<< 12       ' add address (0..7)
  txByte |= (value & $0F) << 5        ' add low nibble 
  txByte |= (value & $F0) << 11       ' add high nibble
  t := cnt                            ' sync
  repeat 21                           ' 20 bits in total + stop
    waitcnt(t += BitTime)             ' wait bit time
    outa[TxPin] := (txByte >>= 1)     ' output bits

but it ai't working
please help me as im sure that im overlookig somthing

Ariba

igor

You don't need to include the simple_serial object. But this is not the problem.
There was a little error in the send routine: the bits are shifted before first bit output.

Try this one:

CON
  TxPin   = 23      ' set your out pin here
  BitTime = 80_000_000 / 19200
   _clkmode = xtal1 + pll16x
   _xinfreq = 5_000_000
 
PUB main 

  dira[TxPin]~~
  outa[TxPin]~~
  repeat
    send(%000,%01010101)
    waitcnt(clkfreq/20 + cnt)   ' a short pause for better scope trigger

PUB Send(addr,value) : txByte | t

  txByte := %11_0000_000_10_1_0000_000_10    ' set start-stop bits
  txByte |= addr<<2 | addr<< 12       ' add address (0..7)
  txByte |= (value & $0F) << 5        ' add low nibble 
  txByte |= (value & $F0) << 11       ' add high nibble
  t := cnt                            ' sync
  repeat 21                           ' 20 bits in total + stop
    waitcnt(t += BitTime)             ' wait bit time
    outa[TxPin] := txByte             ' output bit
    txByte >>= 1                      ' next bit

Andy

Igor_Rast

Thnx Andy , it Work's now > thanks allot