Andrew Mayo wrote:


>Of course. Simply use the Microchip application notes on driving the
>24LCxx devices and create a PIC which programs them - and have it accept
>commands via RS232 so then you have an ultra-low-cost EEPROM programmer.

    Thanks for your suggestion, I will take it in account in case I'll not
find any cheap I2C programmer already done; I'm in touch with  cfb@fast.net
after a suggestion from Andy Kunz (thanks Andy) regarding such a low cost
device.

>I don't understand why you need so much memory for a state machine.
>Normally you need only a byte or two to store the state number (a state
>machine with over 256 finite states would have so much code I don't see
>how you'd implement it in a 16F84). Plus a byte or two to store
>state-associated flags. You start at state 0 and then as events occur
>you move to state x, state y etc. You certainly don't need an n-input X
>m-state array under normal circumstances.

    Andrew, perhaps I haven't got your thought, but it seems strange to me
how to implement a finite state machine without using a 2 dimensions array.
For instance, the state machine I'm implementing to accomplish Manchester
encoding in order to bit bang all the data to LCD module via an RF link has
to manage at least 4 different inputs and has 12 states, so the total
dimension for the array is 4 x 12 bytes, and this is the simplest machine.
If you have the simplest transition model in which from state 0 you move to
state x, y, etc. not considering different inputs and transitions, you don't
need a state machine, that is a straight procedure flow.

>In two bytes I have implemented state and status for quite a complex
>dual-triac zero-crossing temperature controller which also had a control
>keypad, dual LED displays and a Dallas DS1820 temperature sensor. If
>your project is much more complex, are you sure your code will fit into
>1K?.

    I've already coded the whole engine that will "move" the state machines
I need (yes, they are 3 running at the same time in a sort of multitasking)
and it took me 200 bytes. As I'll put the array of data for the state
machines in an external EEPROM, the remaining space I hope will be suffice
for coding the action routines needed to react at state transitions.

    Best regards