| ??? 09/28/06 07:47 Read: times |
#125262 - You didn't answer the question! Responding to: ???'s previous message |
I said:
Sandeep Gupta said:
Presently we are using Philips 89C51X2BN / 89C52X2BN ... 11.0592 crystal on what basis did you decide that this was an appropriate processor? and clock frequency? Sandeep Gupta said:
We are using Philips 89C51X2BN due to need more external code memory You've already said that your application needs 128K of external code - so why did you choose any chip based on an architecture with an inherent 64K limit (like the 8051)?! What made you think that any 8051 would be suitable for an RTOS-based design with 40 tasks? (maybe you did have a good reason - it would help if you shared it) storing small code in microcontroller to protect the software. and rest all in external eprom. That seems a bizarre approach - if only a small amount is in the microcontroller, then only a small amount is protected! The majority of your code - in the external EPROM - is unprotected! Using Serial port; so most suitable crystal 11.0592 Yes, it's a good choice for easy generation of some common baud rates, but that is only one small consideration in the overall system design! The crystal controls the entire operation of the whole chip - how did you decide that 11.0592MHz was fast enough to run a 128K RTOS-based design with 40 tasks?! |
