Hi,
I'm trying to build a circuit with analogue i/o - three analogue inputs, one analogue output, all 0-5v. Two of the inputs will be derived into X & Y pointers for an array stored in the PIC chip (I've not decided on which one yet), or EEPROM if necessary, with the third input value being stored in the array. Essentially, the circuit will construct a lookup table, and switched to 'mode 2' it will send the output by lookup up the output value from this table.
The programming logic I can easily work out myself as I have 20 years experience as a software developer, but I have a few questions about the circuit itself.
The manual contains an ADC circuit, so I'm probably ok there. There's no DAC though that I can find - is there a simple one I can use or do I need another IC for this?
What is the capacity of the PIC memory? From what I can gather it's 128k, can someone confirm this? If it's only 128k it might not have the resolution I want for the array, so how easy is it to interface to an EEPROM?
Can the output current be easily derived from the input current of one of the signals? The reason I ask is because once the array has been populated (probably using a DIP switch on the circuit) the output signal will go to a car ECU to replace one of the inputs - I don't want to fry the ECU.
How easy is it to interrogate and download the contents of the PIC memory and/or EEPROM to my laptop? This would be necessary in order to create a visual of the array, so that I will know when it's been sufficiently populated.
Power supply will be 12-14.5v from the car, I can step this down precircuit if necessary, or can the PIC chip do this?
That's all my newbie questions for now - I'm keen to get the circuit started on the breadboard as I don't think the hardware side will be especially complex. It'll be my first project though and I'm no electronics whizz, so I'm bound to hit some hurdles. Yes, I know I should start by switching LEDs on/off to start with but my style is 'in feet first' and I have a valid use (possibly commercial) for this circuit once I've finished it
Any help appreciated.
Thanks,
Darren
I'm trying to build a circuit with analogue i/o - three analogue inputs, one analogue output, all 0-5v. Two of the inputs will be derived into X & Y pointers for an array stored in the PIC chip (I've not decided on which one yet), or EEPROM if necessary, with the third input value being stored in the array. Essentially, the circuit will construct a lookup table, and switched to 'mode 2' it will send the output by lookup up the output value from this table.
The programming logic I can easily work out myself as I have 20 years experience as a software developer, but I have a few questions about the circuit itself.
The manual contains an ADC circuit, so I'm probably ok there. There's no DAC though that I can find - is there a simple one I can use or do I need another IC for this?
What is the capacity of the PIC memory? From what I can gather it's 128k, can someone confirm this? If it's only 128k it might not have the resolution I want for the array, so how easy is it to interface to an EEPROM?
Can the output current be easily derived from the input current of one of the signals? The reason I ask is because once the array has been populated (probably using a DIP switch on the circuit) the output signal will go to a car ECU to replace one of the inputs - I don't want to fry the ECU.
How easy is it to interrogate and download the contents of the PIC memory and/or EEPROM to my laptop? This would be necessary in order to create a visual of the array, so that I will know when it's been sufficiently populated.
Power supply will be 12-14.5v from the car, I can step this down precircuit if necessary, or can the PIC chip do this?
That's all my newbie questions for now - I'm keen to get the circuit started on the breadboard as I don't think the hardware side will be especially complex. It'll be my first project though and I'm no electronics whizz, so I'm bound to hit some hurdles. Yes, I know I should start by switching LEDs on/off to start with but my style is 'in feet first' and I have a valid use (possibly commercial) for this circuit once I've finished it
Any help appreciated.
Thanks,
Darren