Sending multiple serial strings.

[HenrikOlsson]

Hi,

Why does it "waste" RAM? Could it be stored in ROM instead?

Waste may not have been the best word. What I mean is that the string for each command is static, they don't change, so there's no real need for them to live in RAM - which they'll do if you follow option 1 in my previous post. Again, there's nothing inherently wrong with this and it might be the easiest way if you have the RAM to spare.


It IS stored in ROM (FLASH actually) when you do it like

HESEROUT [$55, $AA, $01, $FF, $00, $00, $AA, $56]

Which means that option 2 does, obviously, use less amount of RAM.

With PBP3 there are ways to create unique usercommands but it's a pretty advanced topic. With the information given so far I'd go for option 2. Create a subroutine for each of the 24 commands and call them in sequence using GOSUB.

/Henrik.

EDIT: And if you DO go for option 2 and want to save some codespace you could probably do that by creating a "send header" and a "send footer" sub so you don't need to store the same 4 bytes for each command 24 times.

mcuStop:
  GOSUB SendHeader : HESEROUT [$01, $FF, $00, $00] : GOSUB SendFooter
  RETURN

SendHeader:
   HSEROUT [$55, $AA]
   RETURN

SendFooter:
   HSEROUT [$AA, $56]
   RETURN

EDIT2: And now, if you use an 18F part and have LONGs enabled you COULD possibly do something like:[code]

Header CON $55AA
Footer CON $AA56
MotorStop CON $01FF0000

mcuStop:
  GOSUB SendHeader : HESEROUT [MotorStop] : GOSUB SendFooter
  RETURN

SendHeader:
   HSEROUT [Header]
   RETURN

SendFooter:
   HSEROUT [Footer]
   RETURN

Watch out for Little vs big endian, I'm not sure, off the top of my head how it's being sent here so you may need to reverse it.