| ??? 11/05/04 03:12 Read: times Msg Score: +1 +1 Good Question |
#80410 - Philips and RC resets. |
The following is what a Philips data sheet has to say about the methods to reset the MCU :
An example of a method to extend the RST signal is to implement a RC circuit by connecting the RST pin to VDD
through a 10 F capacitor and to VSS through an 8.2KW resistor as shown in Figure 5. Note that if an RC circuit is being used, provisions should be made to ensure the VDD rise time does not exceed 1 millisecond and the oscillator start-up time does not exceed 10 milliseconds. Don't think it is a old data sheet. It is from the P89v51RD2 (Rev.02 - 11 Oct 2004 )!! Question is, Why does Philips do such a recommendation ? It is true that they have followed up the above with a paragraph on the bad effects of an improper reset. Quite simply they must have advised the use of a proper Reset controller ? I am sure they must be doing this with a reason. If so what exactly is THAT reason ? Raghu |
