I want to use a 14M2 at default clock to control input and output switching of an audio preamp using latching relays.
Each relay (250R coil) needs 3.75V @ 20ma for 3ms to switch state, and I use a 120uF capacitor between the relay and ground to absorb and then release the voltage from pins switching between high and low to set the relays as needed.
Each 14M2 pin delivers 25ma and, for belt and suspenders security, I am using two pins of the chip to drive each latching relay. In order to avoid connecting an input to an output, I will always first make both pins an input, then make both pins either high or low depending upon how I want the relay to switch.
My question is, do I need to insert a pause between switching both pins to inputs and then switching both to outputs either high or low or can I assume the “input” commands will have completed before the “output” commands execute? When switching to "input" the relays don't move so relay timing is not an issue, only Picaxe timing. If I need a pause, then how long must the pause be? I have no clue.
During normal operation this is not going to be an issue. However, I want virtually instantaneous switching of relays when power is removed either intentionally or accidentally to avoid serious consequences at the power amp and speakers. I will have significant power stored in capacitors for the 14M2 but I want the switching job done ASAP in this circumstance.
Each relay (250R coil) needs 3.75V @ 20ma for 3ms to switch state, and I use a 120uF capacitor between the relay and ground to absorb and then release the voltage from pins switching between high and low to set the relays as needed.
Each 14M2 pin delivers 25ma and, for belt and suspenders security, I am using two pins of the chip to drive each latching relay. In order to avoid connecting an input to an output, I will always first make both pins an input, then make both pins either high or low depending upon how I want the relay to switch.
My question is, do I need to insert a pause between switching both pins to inputs and then switching both to outputs either high or low or can I assume the “input” commands will have completed before the “output” commands execute? When switching to "input" the relays don't move so relay timing is not an issue, only Picaxe timing. If I need a pause, then how long must the pause be? I have no clue.
During normal operation this is not going to be an issue. However, I want virtually instantaneous switching of relays when power is removed either intentionally or accidentally to avoid serious consequences at the power amp and speakers. I will have significant power stored in capacitors for the 14M2 but I want the switching job done ASAP in this circumstance.