3 easy questions about the propeller
FredBlais
Posts: 370
Hi, I have 3 questions about the Propeller:
1- Why the propeller is designed to bootload from the 24LC256, this would not have been easier if it·has 32K Flash memory instead?
2- Is the 24LC256 the only option for serial EEPROM?
3- Are·Parallax planning to support some kind of on-chip-debugger/in-circuit-debugger with breakpoints? (because debugging·using leds or tv is a bit annoying)
Thanks
1- Why the propeller is designed to bootload from the 24LC256, this would not have been easier if it·has 32K Flash memory instead?
2- Is the 24LC256 the only option for serial EEPROM?
3- Are·Parallax planning to support some kind of on-chip-debugger/in-circuit-debugger with breakpoints? (because debugging·using leds or tv is a bit annoying)
Thanks
Comments
1. External device provides room for more functionality inside the chip.
2. Any suitable size 32KB or bigger 24LCxxx device will work.
3. It is unlikely for Parallax to support on-chip debug ability in Propeller.
There are ASM debuggers and simulators available. A C debugger may come later.
Many new-comers have the same question. Good thing Propeller is easy to learn.
Cheers.
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1) Flash memory requires certain kinds of manufacturing steps to prepare the oxide needed for the data storage and the writing of flash memory requires higher voltages than used in the logic circuitry. Both are incompatible with the manufacturing processes used for the Propeller chip.
3) An on-chip debugger would have to be duplicated 8 times. Given the simplicity of the Propeller's processor, this would represent a significant piece of space on an already large chip. There are other major issues involving debugging a multi-processor system. A debugger for ImageCraft's C system is expected eventually. Since this involves an interpreter, some debug support can be added into the interpreter loop. This will slow down execution, but need not be included when not debugging. The Spin interpreter could have debug support added by a 3rd party now that the source code has been published. It would require devoting another cog since the existing interpreter has no room left in its cog for debug support. It would also require that a new Spin compiler be developed which Parallax does not have the resources to do. A 3rd party could now do it, but would not be free.
In addition (grin) to Mike's comments:
1) The additional manufacturing steps translates to added costs per chip. Each additional mask layer in the layout process can cost several thousand dollars depending on the complexity of the mask layer.
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
Noone to now found a bug in the chip and that means: whenever a program doesn't do what you want, wether look to the program again or modify your wishes
(I myself do one and the other)
Post Edited (ErNa) : 7/3/2008 7:14:02 PM GMT
Bugs found in design are often covered in up documentation by statements like <reserved for future use> [noparse]:)[/noparse]
Of course such statements can be honestly portraying the initial intent of the design as well.
Having a debugger helps new developers learn a product. To include one or not is up to the designer.
Whether you need one or not is up to you or your business. That's all I'll say about debuggers now [noparse]:)[/noparse]
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Are there any other bugs, published or not ? ( not including gotchas and traps for the unwary )
There are also these ongoing "my PLL blew up" postings which I know is scaring some people off the Propeller even though the majority don't have problems and it may not be a weakness of the Propeller itself.