Hi people
I have an application that needs constant savings of user data, running on a PC, with a 89c51ed2 based interface connected to its serial port. This data needs to be saved in the mc. Messages to the mc are sent non-stop, PC sends a message, waits for a response and send another, with very few milliseconds of timeout. The problem is, from time to time, mc receives a message with user data to save. Because the time that the flash takes to save data (10mS for each byte i guess), sometimes I get a timeout error on the PC. The problem was 99% solved with walkthroughs and effort.
What I am wondering is, what´s the best method in this case? I was thinking about modifying the hardware to put a large capacitor at the mc VCC, with a port pin conected to the main voltage source. Then i could have a mirror buffer in RAM, and when I sense power-off, imediatelly save the RAM content into the flash. Is this reliable? What would be the best circuit for it?
Thanks in advance.