SX Pin numbering

GAF · 2007-02-22 20:34

Hi,· I have a question on SX/B.· When using the Basic stamp I could use
IN3 to·use pin 3 as an input.· How do I do the same thing in SX/B?

Thanks

Post Edited By Moderator (Bean (Hitt Consulting)) : 2/22/2007 8:52:37 PM GMT

Bean · 2007-02-22 20:53

GAF,
On the SX pins are labeled by their port and position on that port.
For example: RB.0, RB.7, etc.

If you wanted to use pin RB.0 as an input you would do:

INPUT RB.0
IF RB.0 = 1 THEN

Bean.

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Cheap used 4-digit LED display with driver IC·www.hc4led.com

Low power SD Data Logger www.sddatalogger.com
SX-Video Display Modules www.sxvm.com
·

JonnyMac · 2007-02-22 21:36

It's a good idea to declare your I/O pins -- this makes the program easier to read and, with outputs, saves you some setup. For example:

LED     PIN    RC.0 OUTPUT

This will define pin RC.0 as "LED" and make it an output (saving you the trouble) so your program can do this:

LED = 1

Better yet, define constants for on and off like this:

IsOn    CON    1
IsOff   CON    0

... and then do this:

LED = IsOn

See how much easier that is to read/debug -- especially when giving your programs to others?

PJAllen · 2007-02-23 02:50

JonnyMac,

That's so well presented -- that even a hard-core "magic number" like me¹ can get it.

Update --

^·1·However unrepentant.^·

Post Edited (PJ Allen) : 2/23/2007 2:58:05 AM GMT

SailerMan · 2007-03-02 02:21

IT doesn't cause an error, but crashes the IDE. Why?· Is there a solution to this?

DEVICE          SX28, OSCHS1, TURBO, STACKX, OPTIONX, BOR42
FREQ            50_000_000

ID  "Sensor"
 
Sensor Var Byte(8)
 
Sensor(0) Pin RC.3
Sensor(1) Pin RC.2
Sensor(2) Pin RC.1
Sensor(3) Pin RC.0

Sensor(4) Pin RB.3
Sensor(5) Pin RB.2
Sensor(6) Pin RB.1
Sensor(7) Pin RB.0
 
Temp Var Byte

 
PROGRAM Start  
 
Start:
          
Main:
  
Do
  For Temp=0 to 7
    Pulsout Sensor(Temp),100,25
  Next 
  Pause 250
Loop

Post Edited (SailerMan) : 3/2/2007 12:14:51 PM GMT

PJAllen · 2007-03-02 02:58

IT doesn't like the array that you're trying to set up.
Is this what you're trying to do?

DEVICE sx28, oschs3, TURBO, STACKX, OPTIONX
IRC_CAL  IRC_SLOW
FREQ     50_000_000
PROGRAM Start 
ID  "Sensor"
Start:
 
 
Sensor0 Pin RC.3
Sensor1 Pin RC.2
Sensor2 Pin RC.1
Sensor3 Pin RC.0
Sensor4 Pin RB.3
Sensor5 Pin RB.2
Sensor6 Pin RB.1
Sensor7 Pin RB.0
  
  Do
  Pause 250
  Loop

Update -- Forgot to add that this much compiles.· It's disallowing combining an array and Pin Numbering.· I think that you'll need to add input/output after the Pin Number, too [noparse]/noparse]i.e. [i]Sensor Pin RC.3 INPUT[/i

Post Edited (PJ Allen) : 3/2/2007 3:07:33 AM GMT

JonnyMac · 2007-03-02 04:07

Pin names must conform to label specs: up to 32 characters, must start with an alpha, the only non-alphameric character allowed is underscore. If you inputs are simple digital inputs then there is an easy way to iterate through them as your declarations suggest you want to do.

Bean · 2007-03-02 11:38

SX/B does not support bit arrays.
I will look into the crashing, it should cause an error.

Bean.

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Cheap used 4-digit LED display with driver IC·www.hc4led.com

Low power SD Data Logger www.sddatalogger.com
SX-Video Display Modules www.sxvm.com
Coming soon! Propeller based OSD module www.hittconsulting.com
·

SailerMan · 2007-03-02 12:11

Bean,

Is there a good way to do what I'm trying to do in the above code?

I need to iterate through non sequential pins.

Regards,

Eric

Bean · 2007-03-02 14:02

Eric,
You can use a bit mask.
It would be alot easier if you connected all the sensors to one port (either RB or RC).

Will the order change at runtime ? If not then just change the connections so they are in order.

Assuming you are using the RB port for all sensors, and the array bitPos holds the bit position of the sensor to pulse, you would do:

FOR temp = 0 TO 7
· mask = 1 << bitPos(temp)
· RB = RB XOR mask ' Invert bit
· PAUSE 25 ' PULSOUT x, 100, 25 = 25 mSec
· RB = RB XOR mask ' invert bit
NEXT

Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Cheap used 4-digit LED display with driver IC·www.hc4led.com

Low power SD Data Logger www.sddatalogger.com
SX-Video Display Modules www.sxvm.com
Coming soon! Propeller based OSD module www.hittconsulting.com
·

SailerMan · 2007-03-02 14:34

I was going to put them all on the same port, but the layout and routing of my board was so much easier.

I guess that I will have to spend some more time re-routing my board and just use Port RB. It seems the most Logical course of action... Thanks for your code snipet.

Regards,
Eric

Bean · 2007-03-02 15:03

Eric,
· If you want to use both RB and RC then you just need to make "mask" a Word variable and use RBC.
· bitPos() elements can be from 0 (RB.0) to 15 (RC.7)

FOR temp = 0 TO 7
· mask = 1 << bitPos(temp) ' mask is a WORD variable
· RBC = RBC XOR mask ' Invert bit
· PAUSE 25 ' PULSOUT x, 100, 25 = 25 mSec
· RBC = RBC XOR mask ' invert bit
NEXT

· I always optimize my layouts and adjust the software to work. It's much easier to make a software mod, then a hardware mod.

· The drafting dept as work loves me because I don't show what pin a connection is to on the SX. I just say "It can be connected to any of these pins". It really freaks them out, they are not used to being able to do that. Then I always find lots of ways to simplify the layout after they do it, by using a different pin for something.

· Just don't forget about I2C pins, they must be in a specific order. I've got them backwards a couple times then the SX/B I2C commands don't work.

Bean

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Cheap used 4-digit LED display with driver IC·www.hc4led.com

Low power SD Data Logger www.sddatalogger.com
SX-Video Display Modules www.sxvm.com
Coming soon! Propeller based OSD module www.hittconsulting.com

Post Edited (Bean (Hitt Consulting)) : 3/2/2007 3:10:16 PM GMT

SailerMan · 2007-03-02 15:53

It took me a sec, but I see the you're·creating a pulsout with this.

RBC = RBC XOR mask ' Invert bit
PAUSE 25 ' PULSOUT x, 100, 25 = 25 mSec
RBC = RBC XOR mask ' invert bit

·So I should define an Array of Bit Positions.

What is the Best Way to load the Array with Bit Position info.

BitPos(0) = %0000_0000_0000_1000
BitPos(1) = %0000_0000_0000_0100
BitPos(2) = %0000_0000_0000_0010
BitPos(3) = %0000_0000_0000_0001

BitPos(4) = %0000_1000_0000_0000
BitPos(5) = %0000_0100_0000_0000
BitPos(6) = %0000_0010_0000_0000
BitPos(7) = %0000_0001_0000_0000

Am I thinking of this in the right way? I'd test it but I 'm not at home.

Regards,
Eric

Post Edited (SailerMan) : 3/2/2007 3:59:47 PM GMT

Guenther Daubach · 2007-03-02 16:12

Hi,

maybe, this is a bit off-topic here as I'll show examples in ASM here, and not in SX/B...

In general, I agree with Bean that assigning SX I/O pins to specific signals can be arbirtrary in most cases. Nevertheless, sometimes, it makes software design easier, or more compact when you use specific pins. For example, in a serial receiver code, you will often find the instruction

movb C, RxD

where RxD can be any port pin used as serial input. The movb instruction is a compound instruction, i.e. expanded to

sb RxD
clrb C
snb RxD
setb C

so it takes four program words, and four clock cycles for execution.

If you were using RB.7 as RxD input pin, for example, you could move the status of RxD into the C flag with just one instruction:

mov w, <<RB

This moves the left-rotated contents of RB into w but also rotates bit 7 of RB into the C flag.

You can also use RB.0, for example, together with

mov w, >>RB

Besides this, keep in mind that only the port B inputs allow for wake-up, and interrupts, and the RA pins can't be configured as Schmitt-Trigger but they have symmetric source/sink characteristics when configured as outputs.

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Greetings from Germany,

G

Bean · 2007-03-02 16:33

Eric,
No, you just want to put the bit position VALUE into the array.

0 to 7 = RB.0 to B.7 ; 8 to 15 = RC.0 to RC.7

So:

PUT bitpos, 11, 10, 9, 8, 3, 2, 1, 0

Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Cheap used 4-digit LED display with driver IC·www.hc4led.com

Low power SD Data Logger www.sddatalogger.com
SX-Video Display Modules www.sxvm.com
Coming soon! Propeller based OSD module www.hittconsulting.com
·

SailerMan · 2007-03-02 16:34

Gunther,

That was way over my head but thanks. [noparse]:)[/noparse]

Bean,

Great thanks for clarifying that for me.

Regards,
ERic

Post Edited (SailerMan) : 3/2/2007 4:38:52 PM GMT

SX Pin numbering

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