moving over from Stamp programming to the Propeller world

Steve2381

Hello.

I am moving over from Stamp programming to the Propeller world. Any pointers as to its abilities and skills would be greatly received!
I understand it has audio and video capabilities. What does it actually allow you to do?
Finally... is the programming a far leap from Stamps?

Many thanks!.... looking forward to hours of programming

Steve

Post Edited By Moderator (Bean (Hitt Consulting)) : 12/12/2009 10:55:00 PM GMT

localroger

Steve, if you can program stamps you can program propellers; much of the hard work has been done by people who write standard objects posted in the object exchange. The best advice is to get one and try to make it do something -- probably how you got started in stamps. It's possible to make a Prop do useful things with little knowledge at all once you learn the basic Spin stuff and how to use the objects. And over time you'll hunger for more, and you'll get into more advanced techniques, writing more complex Spin code and PASM. Jump in, the water's fine -- and shallow in places if you want to go slowly.

StefanL38

Hello Steve,

so the main difference between PBasic and spin is that pbasic has more sophisticated commands
than you have in SPIN.
PBasic example

  SERIN RX\RTS, Baud, 100, No_Data, [noparse][[/noparse] ioByte ] 

in PBASIC the serin-command is hardcoded and you can't change its behaviour.
The only variance is to call the command with different values for the parameters.

In SPIN the "high-sophisticated" commands are realized through the combination of
basic commands

example receive a serial byte is done by the code

PUB Rx : rxbyte
  '' Receives byte (may wait for byte)
  '' rxbyte returns $00..$FF

  repeat while (rxbyte := rxcheck) < 0

"PUB" indicates a subroutine (similar to a label in PBasic

"Rx" is the name of the subroutine

repeat while are elementary SPIN-commands

the command "rxcheck" inside the subroutine "Rx" is another subroutine
defined or "build" with elementary SPIN-commands

PUB RxCheck : rxbyte

  '' Check if byte received (never waits)
  '' rxbyte returns -1 if no byte received, $00..$FF if byte

  rxbyte--
  if rx_tail <> rx_head
    rxbyte := rx_buffer[noparse][[/noparse]rx_tail]
    rx_tail := (rx_tail + 1) & BUFFER_MASK

now the command "if" used in "RxCheck" is a REAL elementary SPIN-command

all the rest are variables that are nescessary to make it work but the variables are not important for the user

This means: in SPIN more complex commands are not "hardwired" like in PBasic
they are build out of elementary commands by defining sub-routines

Objects in SPIN are simply SPIN-files containing a collection of subroutines all build with the elementary set of SPIN-commands
which provide complex commands. In the code-example above a command to receive a byte over a serial connection

Now you may ask where are the parameters like IO-pins and baudrate ?
the parameters IO-pins and baudrate have to be configured ONE time.

The propeller-chip has 8 processor cores. These cores are called "COGs"
All the bitbanging for send and receive serial data is done by a second COG which works as a "driver" in the background
This cog has to be started before you can do serial communication.
This means a part of the code inside the file FullDuplexSerialPlus.spin is executed in the second COG running ALL THE TIME
waiting for serial data to be received and transmitted. This part of the code runs parallel to the first COG.

You can imagine this driver as if you would have a butler listening for the doorbell and as soon as he hears the doorbell
going to the door open it and take in the presents that are delivered. And listening for orders to bring some documents
to Mister A, oder Mister B

There is an object for serial communication, for creating a TV-signal, VGA-Signal etc., etc., etc.

If you want to use these complex commands you define a "connection" between the filename and an object-name

OBJ
  Debug   : "FullDuplexSerialPlus"    'short name FDX+
'   │            │
'   │            └this is the filename WITHOUT extension ".spin"
'   │
'   └this is the objectname 

after defining this name "Debug" you can access the omplex SPIN-commands wich are defined in the file FullDuplexSerialPlus.spin

by writing ObjectName.Methodname

in the example above to receive a byte

  MyByte := Debug.Rx 

best regards

Stefan

Steve2381

Thanks for the replies. Looks like the best plan is to get a starter kit and dive in. Stamps are fine, but too slow and expensive.
I will have a look for a decent starter kit and loose my evenings for the rest of winter!
Thanks
Steve

Tony B.

As a beginner I would recommend under the Propeller Tool help menu,

1. The Propeller Education Kit Manual
2. Propeller Help…. Which is the old tutorial that was in the Propeller Manual 1.0. (The new version 1.1 doesn't have it)

As a beginner I have found them to be a great help and introduction to programming the Propeller chip.