| ??? 07/27/09 14:15 Read: times |
#167929 - is 17 a very large number? ;-) Responding to: ???'s previous message |
Per Westermark said:
Richard: Is 8 pins a "lot of pins"?
Note that I did write (emphasis added): "But the big problem is that the price is sky-high even at 500-quantity, and that it is a parallel chip, requiring a very large number of processor pins." I was not discussing the SD interface, but the chip in this link: http://search.digikey.com/scripts/D...-1413-1-ND Unless I goofed up, it has 17 signal lines to reach 2GB/16Gbit which is significantly more than needed for a SD memory. First, you can tie together both ready/busy pins. That makes 16. Then, you don't need the ready/busy at all (if you poll the status register), nor write protect (could be tied to high). That's 14. And the true point is, that if you already have an external memory bus, the real pin consumption is 1 or 2 (for dedicated chip selects - unless they are manged by some sort of an address decoder). But, even if it would be 17, that does not really qualify for a "very large number" in my dictionary of microcontroller terminology. Besides, I pointed to a chip which *can* be bought in quantity of 1, now. Show me your solderable SD module. JW |
