SEROUT 9600 8E2

Comments

• JonnyMac Posts: 9,309

  2017-01-19 20:52 edited 2017-01-19 21:02

  Can you do parity with 8 bits? I'm not sure you can (because the 8th bit IS the parity bit).
  
  If you are looking for extra time between bytes, you can use the optional pace parameter of SEROUT.
  
  In my BASIC Stamp 2 template I have a conditional section that handles details -- I edited for 9600 baud, even parity
  

  #SELECT $STAMP
  
    #CASE BS2, BS2E, BS2PE
      T1200       CON     813
      T2400       CON     396
      T4800       CON     188
      T9600       CON     84
      T19K2       CON     32
      T38K4       CON     6
  
    #CASE BS2SX, BS2P
      T1200       CON     2063
      T2400       CON     1021
      T4800       CON     500
      T9600       CON     240
      T19K2       CON     110
      T38K4       CON     45
  
    #CASE BS2PX
      T1200       CON     3313
      T2400       CON     1646
      T4800       CON     813
      T9600       CON     396
      T19K2       CON     188
      T38K4       CON     84
  
  #ENDSELECT
  
  SevenBit        CON     $2000
  Inverted        CON     $4000
  Open            CON     $8000
  
  Baud            CON     T9600 | SevenBit
  

  You can add the pacing like this:

    SEROUT Sio, Baud, 1,  [$FE,$FE,$FE,$05,$04,$00,$05,$0D,$E5]
  

  You'll get 1ms between bytes -- hopefully, your device will be okay with this.
• JonnyMac Posts: 9,309

  2017-01-19 21:02

  Now that I look at your data -- you can't use 7-bit transmission because some of your bytes have bit7 set.
  
  What are you sending the data to?
• Jkane Posts: 113

  2017-01-20 00:28

  Well, I originally coded it in assembler, which worked fine, since I just used a logic scope and converted the signal to high/low with delays, but I recently used the c version of prop, used the serial.h, but couldn't match the signal, so since basic stamp seemed to allow more flexibility, I switched over, but still couldn't match the signal, then I checked ,some old notes and they used 8E2, 9600, so I just thought it there was a,way I could get rid of all the assembler code, easier to read. Could I use a uart?, and then have more options? The signal is exactly 10.44 ms long and sends the 9 bytes above, I also tried us delays between bytes but got no return data,
  
  I'll add a logic trace of the working signal tomorrow.
  
  Regards
  
  Jeff
• kwinn Posts: 8,697

  2017-01-20 03:00 edited 2017-01-20 03:01

  I'm almost 100% certain that you could do 8 bits with parity, which made for a minimum of 11 bits (1 start + 8 data + 1 parity + 1 stop bit) on some of the older uart chips. That 11 bit times per character requirement sticks in my memory even though I can no longer recall the specific application any longer. A bit frustrating that, but a lot of bits have passed under the bridge.
  
  EDIT Of course 8E2 would be 12 bits.
• Jkane Posts: 113

  2017-01-20 03:17

  yes, 8E2 is 12 bits, so can basic stamp or propeller do 12 bits? (or even the sx microprocessor) I like the propeller and parallax hardware and really don't want to add additional HW or microprocessors, all other functions for interfacing work fine, this is the last issue.
  
  regards
  
  jeff
• kwinn Posts: 8,697

  2017-01-20 03:22

  Jkane wrote: »

  yes, 8E2 is 12 bits, so can basic stamp or propeller do 12 bits? (or even the sx microprocessor) I like the propeller and parallax hardware and really don't want to add additional HW or microprocessors, all other functions for interfacing work fine, this is the last issue.
  
  regards
  
  jeff

  
  For sure the Propeller can do 12 bits but it would require changing the pasm code to add the parity bit and a second stop bit.
• Duane Degn Posts: 10,588

  2017-01-20 04:37

  Tracy Allen helped me modify his four port serial driver, written in Spin/PASM, to use even parity on one channel. I'll see if I can find a link to the forum thread discussing this modification.
• Duane Degn Posts: 10,588

  2017-01-20 04:42

  Here's the thread where Tracy kindly (as usual) helped me figure out how to add even parity.
  
  I attached a version of the driver to this post.
  
  The driver can be used from multiple objects and cogs. Just make sure and only call "Init" and "Start" from a single object and cog.
• Jkane Posts: 113

  2017-02-11 13:43

  
  Hello, well I temporally went to another microprocessor to validate the return data from the device, but it is messy, adds to much complexity for the needed result, so I'm back I'll test your suggestions.
  thank you for your help, from what I read, it should work fine, regards Jeff