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Maximum Usable Baud Rates for SERIN Formatting Options — Parallax Forums

Maximum Usable Baud Rates for SERIN Formatting Options

I measured the maximum SERIN baud rates for a number of formatting options and three flavors of BS-2. A summary is attached. The BS-2 program used to make the measurements and the Prop program used to generate the test strings are attached.

The summary has a row for each baud rate. The "standard" baud rates are shown in bold text. Each row shows the results for each of three flavor of BS-2. For each flavor, there are four columns. First is the baud rate code, then a column indicating the results for STR/SPSTR, a column for Decimal, Hexadecimal formats, and a column for WAIT/WAITSTR and SKIP. The green area indicates that function worked correctly at the indicated baud rate.

For every flavor, bare STR/SPSTR supports the highest baud rate. If you have a situation where the baud rate absolutely cannot be reduced, you can perhaps at least capture the incoming string. Of course, you must then parse the string by hand (no DEC/HEX, for example).

The DEC and HEX formatters take time and so the maximum baud rates are reduced.

The slowest are the SKIP and WAIT/WAITSTR qualifiers. I combined SKIP with WAIT as well as SKIP with WAITSTR in my testing.

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    The results look about like I would expect. I remember we used to use the STR formatter and set the original PSC to 38,400 bps with the BS2. So many think it can't do 9600+ but it sure can. :nerd:
  • That's a great report Tom.! I know people will benefit from it down the road.
  • Tom,

    That's great work. I've used 38400 on the BS2 with STR and it works just like you showed. Any chance you have a BS2sx you can test and add to your table?
  • I added BS2sx to the table. The baud rate codes are the same as BS2p; they are duplicated in the table.
  • Thanks Tom. Looks like the SX tops the P for the STR command at 115200 rate, interesting! I like this chip, except for the fact it lacks the I2C commands.
  • It also lacks SPSTR, so you are pretty limited when it comes to just capturing strings.
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