Memory Chip Addressing

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Memory Chip Addressing

pvtjokerdavis
I've been trying to figure out how the addressing will work for the Memory chip. I understand that the two most significant bits, address[13] and address[14] can be used to determine which part of the memory should be accessed. But it's confusing because the RAM16K chip accepts a 14-bit wide address input, the SCREEN takes a 13-bit wide address input, and the KBD register doesn't have an address input. The Memory chip as a whole takes a 15-bit wide address input. Is the configuration similar to that of the RAMs? Feeling confused
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Re: Memory Chip Addressing

cadet1620
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pvtjokerdavis wrote
I've been trying to figure out how the addressing will work for the Memory chip.  I understand that the two

most significant bits, address[13] and address[14] can be used to determine which part of the memory

should be accessed. But it's confusing because the RAM16K chip accepts a 14-bit wide address input, the

SCREEN takes a 13-bit wide address input, and the KBD register doesn't have an address input. The Memory

chip as a whole takes a 15-bit wide address input. Is the configuration similar to that of the RAMs? Feeling

confused
Yes, Memory is the same general idea as the RAM chips, but the address space for the sub-components consists of different sized blocks.  Just hook the matching number of low order address bits to the RAM and Screen and control their load based on the upper bits.  All three parts are always generating outputs, just like the RAMs inside a bigger RAM, so you also need to use the upper address bits to select which part's output gets sent to the Memory's output.

--Mark
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Re: Memory Chip Addressing

pvtjokerdavis
Thank you, sir and comparison ended successfully.