I need urgent help on a question, deadline TOMORROW UK time, and although it may not be of general interest to the list, I'm sure there are many of you who will know the answers.
The question is this: [quote] The main memory of a microprocessor system consists of the following mmemory sections: 512K ROM 256 video RAM 128K general-purpose RAM 128K special battery-backed, non-volatile RAM Assume the above sections of memory are located contiguously in the order given above (i.e. the start of the ROM is at address 0, the start of the video RAM follows on directly from the end of the ROM and so on) and that the memory sections completely fill the microprocessor's main memory address space. (a) How many address lines do the following sections of memory need? (i) the ROM (ii) the general-purpose RAM (b) How many address lines does the microprocessor have? [unquote] I've worked out, I hope correctly, that the address blocks are as follows: ROM 00000h to 7FFFFh Video RAM 80000h to BFFFFh Gen. purpose RAM - C0000h to DFFFFh non-volatile RAM - E0000h to FFFFFh Having spent hours researching the question on the internet (there's no-one to help as I'm doing a distance-learning course and get no feedback at all) -- I found so much conflicting information on address lines and how to calculate memory amounts that I am more confused than ever. There seem to be different figures and methods of calculation depending on whether one is talking about real-mode, protected-mode, or the memory chips themselves. In fact, what is understood by address lines? the number of lines on the address bus or the number of linear locations in memory?? Or ...? Is it correct that 1M of memory needs 20 address lines?? How does one go about calculating the lines required by the different sections of memory. The answer is probably simple but I've become so confused that I can't get my head round it. If anyone can elucidate, please email me off-list ASAP, as the matter has become urgent and I can't wait to receive tomorrow's PCWorks digest. I know there are lots of you who will have the answer ... Thanks a million Virginia ============= PCWorks Mailing List ================= Don't see your post? Check our posting guidelines & make sure you've followed proper posting procedures, http://pcworkers.com/rules.htm Contact list owner <[EMAIL PROTECTED]> Unsubscribing and other changes: http://pcworkers.com =====================================================
