What is the rate you want to read data back off the seeprom? The seeprom has 5mA max rating while writing for a clock rate of 400kHz. The SX consumes a max of 82 mA @ 50MHz, 8 mA @ 4 MHz. So you cable should be able to supply at least 150mA for 50MHz or 75mA for 4MHz (you always give a healthy margin to be safe, we don't want any electrical fires).
Im glossing over supply consumed by pins switching, another reason to give a healthy margin.
oh yeah and you need to add the power the device your sharing the power with. Im strongly leaning to you under clocking the SX to something like 10-20MHz (4MHz would probably work too, since your just recording and replaying events, no computations on data needed)
Post Edited (Paul Baker) : 1/12/2005 9:30:23 PM GMT
Paul Baker said...
What is the rate you want to read data back off the seeprom?
Slowly. I haven't decided on an exact rate yet but read speed is not an issue. Most likely the read speed will be 20 or 30 bytes per second (prefferably as fast as possible though).·It is made slightly easier by the fact that the "terminating device" as I called it is cut off when log playback is being done (my device·emulates the terminating device and ignores any input from it) so all I have to keep track of is reading, I don't have to worry about other events happening during playback.
Also, I redid some calculations and realized that the write speed could need to be slightly faster than I meantioned before. About how many bytes do you you figure that memory you meantioned can write per second? The data sheet says the write time is 10ms so would I be correct is assuming it can write up to 100 bytes per second?
yeah that sounds right, in that case I would definitely shift down the speed of the SX, if for nothing else to make sure there are no power supply issues. A 8MHz clock at first glance sounds like a happy medium, at that frequency the SX would consume about 12mA. We can swap out the resonator later if thats not fast enough.
Post Edited (Paul Baker) : 1/12/2005 9:47:06 PM GMT
Yeah, I will definately shift down the speed of the SX. Especialy since the clock speed of the "Terminating device" is only
10-16.7 kHz.
Well then, I will order that chip tonight and it looks like until I get the chip, you have answered all my questions.
I thank you verry much for your help.
I am sure I will have many questions when I actually start to program the chip to interface with memory.
WARNING!! The '-2.7' in your EEPROM part number, AT24C1024-10PI-2.7,·is probably·the operating voltage of this IC. Confirm that before you do anything, as 5V in may destroy it. Perhaps the part will·survive on 5V, but the logic part won't function. You could regulate the 5V down to 2.7V with a Zener diode and a resistor, but the logic levels may not be suitable for each other. *sigh*
Parts can be installed on both sides in a double-sided board. The first side has a small drop of adhesive applied at every position before parts placement, which is cured during the first run through the oven. The other side is then solder pasted and parts installed. The second side is then cooked with the original parts, now upside down,·held in place by the adhesive.
As for board design and production, check out pcbexpress.com. They provide a PCB design package, PCB123, you can download and use for free. It is limited in the number of parts you can place and the dimensions of the board, but your present project sounds like this will do the job nicely. You create a schematic from a library of predrawn parts.·You then·go to board layout, where you·place the parts and autoroute the traces. The program even supplies an estimate for board(s) fabrication.
Hope this helps.
kenjj
All my pencils *used* to have erasers!
WARNING!! The '-2.7' in your EEPROM part number, AT24C1024-10PI-2.7,·is probably·the operating voltage of this IC. Confirm that before you do anything, as 5V in may destroy it. Perhaps the part will·survive on 5V, but the logic part won't function. You could regulate the 5V down to 2.7V with a Zener diode and a resistor, but the logic levels may not be suitable for each other. *sigh*
From the data sheet...
Also, thank you for the link to pcbexpress.com. I was looking at them earlier today but I will give them a second look.
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Andrew Curioso
IG3D Media
Post Edited (IG3D Media) : 1/13/2005 3:19:07 AM GMT
Umm, Andrew, it is conceivable the 2.7 to 5.5 volts is NOT for a 'single part', but is instead for a RANGE OF PARTS. If they put "-2.7" as part of the part number, this seems more likely.
And then, now that I've checked the manufacturer's data sheet, it merely seems they are so proud they got a device that goes down that low, they put it as part of the part number. The "-2.7" does go from 2.7 volts to 5.5 volts -- their so-called "Low-Power" device.
Note it is a 1024 KBit device -- 512 pages of 256 bytes each is 131,072 bytes, or 1,048,576 bits. Sigh. Still not very shabby, compared to all those 8K and 32K eeproms out there.
Comments
Im glossing over supply consumed by pins switching, another reason to give a healthy margin.
oh yeah and you need to add the power the device your sharing the power with. Im strongly leaning to you under clocking the SX to something like 10-20MHz (4MHz would probably work too, since your just recording and replaying events, no computations on data needed)
Post Edited (Paul Baker) : 1/12/2005 9:30:23 PM GMT
Also, I redid some calculations and realized that the write speed could need to be slightly faster than I meantioned before. About how many bytes do you you figure that memory you meantioned can write per second? The data sheet says the write time is 10ms so would I be correct is assuming it can write up to 100 bytes per second?
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Andrew Curioso
IG3D Media
Post Edited (Paul Baker) : 1/12/2005 9:47:06 PM GMT
10-16.7 kHz.
Well then, I will order that chip tonight and it looks like until I get the chip, you have answered all my questions.
I thank you verry much for your help.
I am sure I will have many questions when I actually start to program the chip to interface with memory.
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Andrew Curioso
IG3D Media
WARNING!! The '-2.7' in your EEPROM part number, AT24C1024-10PI-2.7,·is probably·the operating voltage of this IC. Confirm that before you do anything, as 5V in may destroy it. Perhaps the part will·survive on 5V, but the logic part won't function. You could regulate the 5V down to 2.7V with a Zener diode and a resistor, but the logic levels may not be suitable for each other. *sigh*
Parts can be installed on both sides in a double-sided board. The first side has a small drop of adhesive applied at every position before parts placement, which is cured during the first run through the oven. The other side is then solder pasted and parts installed. The second side is then cooked with the original parts, now upside down,·held in place by the adhesive.
As for board design and production, check out pcbexpress.com. They provide a PCB design package, PCB123, you can download and use for free. It is limited in the number of parts you can place and the dimensions of the board, but your present project sounds like this will do the job nicely. You create a schematic from a library of predrawn parts.·You then·go to board layout, where you·place the parts and autoroute the traces. The program even supplies an estimate for board(s) fabrication.
Hope this helps.
kenjj
All my pencils *used* to have erasers!
Also, thank you for the link to pcbexpress.com. I was looking at them earlier today but I will give them a second look.
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Andrew Curioso
IG3D Media
Post Edited (IG3D Media) : 1/13/2005 3:19:07 AM GMT
And then, now that I've checked the manufacturer's data sheet, it merely seems they are so proud they got a device that goes down that low, they put it as part of the part number. The "-2.7" does go from 2.7 volts to 5.5 volts -- their so-called "Low-Power" device.
Note it is a 1024 KBit device -- 512 pages of 256 bytes each is 131,072 bytes, or 1,048,576 bits. Sigh. Still not very shabby, compared to all those 8K and 32K eeproms out there.
This part is a low voltage part which can also be driven at 5V
Sorry I quoted the 8-LAP device, but it says the same thing for the 8-DIP device.
Voltage level is the first thing I check, I never make that mistake.
Paul
PS cool I can force the post out beyond the default length, I didnt know what it would do
Post Edited (Paul Baker) : 1/13/2005 7:38:19 PM GMT
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Andrew Curioso
IG3D Media