Twenty Log
Well-known member
Howdy...
Just kicking an idea around to figure out... I have maybe 13 MOMENTARY push buttons that affect various analog circuit parameters...
These momentary push buttons use D flip flops to toggle the state of circuit modifiers in the analog circuits...
There is no microprocessor in this design....
The thing is, when the lights go out, the D flip flops lose their state (of course)....
Is there a way to back up the D flip flop states?
I was thinking an SRAM chip with battery backup, that gets new state information updates when buttons are pressed or D flip flops get updates upon power on reset (POR) from the SRAM....
However, I think a super/ultra capacitor would be better than a battery... would last for a few days, which is plenty...
I found some NV SRAM chips, with special power failure to quantum trap NV RAM from Cypress (that are NRND), but they are ghastly expensive, and I do not need 4MB (just 13 bits or so)....
SRAM seems to be less expensive, but it is hard to find just a tiny parallel SRAM that is not too expensive...
The other issue is that with 13 states to backup, an x8 SRAM will now need some sort of state machine or clock to get 13~14 bits into it... maybe not a problem here, but just a consideration..
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So the question is, is there a simple SRAM or static type logic that can save state with an ultra cap for a few days or so without the use of a microprocessor?
The switches cannot be changed and will be momentary....
Interesting puzzle....
Just kicking an idea around to figure out... I have maybe 13 MOMENTARY push buttons that affect various analog circuit parameters...
These momentary push buttons use D flip flops to toggle the state of circuit modifiers in the analog circuits...
There is no microprocessor in this design....
The thing is, when the lights go out, the D flip flops lose their state (of course)....
Is there a way to back up the D flip flop states?
I was thinking an SRAM chip with battery backup, that gets new state information updates when buttons are pressed or D flip flops get updates upon power on reset (POR) from the SRAM....
However, I think a super/ultra capacitor would be better than a battery... would last for a few days, which is plenty...
I found some NV SRAM chips, with special power failure to quantum trap NV RAM from Cypress (that are NRND), but they are ghastly expensive, and I do not need 4MB (just 13 bits or so)....
SRAM seems to be less expensive, but it is hard to find just a tiny parallel SRAM that is not too expensive...
The other issue is that with 13 states to backup, an x8 SRAM will now need some sort of state machine or clock to get 13~14 bits into it... maybe not a problem here, but just a consideration..
-----
So the question is, is there a simple SRAM or static type logic that can save state with an ultra cap for a few days or so without the use of a microprocessor?
The switches cannot be changed and will be momentary....
Interesting puzzle....