We still seem to be ignoring the additional need for 256 inputs and any determination of a minimal processing speed. A BasicStamp or SX48 could handle 256 inputs and 256 outputs if lower turnaround speed were acceptable.
It might be necessary to allocate 8 cogs to a sub-group to get the kind of performance one expects. All these shift registers downgrade the response time due to the multiple shifts. One chain of 256 shifts would eat up at least 256 clock cycles. 80Mhz/256 = 312.5Khz response as the other 255 pins are waiting for the next round.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Ain't gadetry a wonderful thing?
@Loopy Byteloose
Even if it takes 1 µs per bit (with all the overhead) this would be roughly 0.25ms for 256 bits. Do you think that's too slow for a telephone application?
Nick
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Never use force, just go for a bigger hammer!
The DIY Digital-Readout for mills, lathes etc.: YADRO
Its telephone-"esque" if I may say [noparse]:)[/noparse]· Not using actual telephones at all, no "dialing" in the traditional sense.
Its a communication system which is currently driven by a person activating one of 212 relays by pushing one of 212 buttons. (It seems so barbaric to do it this way it makes me laugh every time I describe this)
Its a Many -> One situation. The "Many" can only·speak with the "One"..not each other.
I'm only in a position to change·the "One" side of the system.
Speed...not really anything to consider here accept in terms of writing the relay driving software on the prop.
Why use a prop instead of another MCU?
1) The savings...even the entire cost of the propeller chip ($8) is likely to be less than 100th of·one percent of the cost of the project, so saving any $$ on using another MCU doesn't make sense for me if I have to learn something else.
2) There is a video portion to this project, a display of which apt is being called..which apt is calling...last 10 calls...Display the time...etc. So right there the prop has me covered in a way that I don't think I'll be able to find with another MCU.
3) Even if there were 10 other MCUs that did what the prop does and they where all free, I would still use the prop. (Yeah...I'm a fanboy I guess...and I'm OK with that )
Comments
It might be necessary to allocate 8 cogs to a sub-group to get the kind of performance one expects. All these shift registers downgrade the response time due to the multiple shifts. One chain of 256 shifts would eat up at least 256 clock cycles. 80Mhz/256 = 312.5Khz response as the other 255 pins are waiting for the next round.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Ain't gadetry a wonderful thing?
aka G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan
Even if it takes 1 µs per bit (with all the overhead) this would be roughly 0.25ms for 256 bits. Do you think that's too slow for a telephone application?
Nick
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Never use force, just go for a bigger hammer!
The DIY Digital-Readout for mills, lathes etc.:
YADRO
Its telephone-"esque" if I may say [noparse]:)[/noparse]· Not using actual telephones at all, no "dialing" in the traditional sense.
Its a communication system which is currently driven by a person activating one of 212 relays by pushing one of 212 buttons. (It seems so barbaric to do it this way
Its a Many -> One situation. The "Many" can only·speak with the "One"..not each other.
I'm only in a position to change·the "One" side of the system.
Speed...not really anything to consider here accept in terms of writing the relay driving software on the prop.
Why use a prop instead of another MCU?
1) The savings...even the entire cost of the propeller chip ($8) is likely to be less than 100th of·one percent of the cost of the project, so saving any $$ on using another MCU doesn't make sense for me if I have to learn something else.
2) There is a video portion to this project, a display of which apt is being called..which apt is calling...last 10 calls...Display the time...etc. So right there the prop has me covered in a way that I don't think I'll be able to find with another MCU.
3) Even if there were 10 other MCUs that did what the prop does and they where all free, I would still use the prop. (Yeah...I'm a fanboy I guess...and I'm OK with that
Rick
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Prop Forum Search (Via Google)