Em 21/8/2010 09:54, Oli Glaser escreveu: > > -------------------------------------------------- > From: "Isaac Marino Bavaresco" > Sent: Saturday, August 21, 2010 1:04 PM > To: "Microcontroller discussion list - Public." > Subject: Re: [EE] Programmable logic > >> CPLDs are better for small designs because they don't boot from an >> external memory like most FPGAs. > True, that's why I suggested the Actel parts though if the OP does want t= o=20 > go for an FPGA, as they are mostly based on Flash memory. > >> There are CPLDs with macrocell counts from a few tens to a few hundreds. >> A macrocell is much more than simply "one gate". > Yes, as I understand it, a macrocell can be different for different vendo= rs,=20 > though usually something like a 3 or 4 input LUT with a mux and flip flop= ,=20 > enabling them to perform a range of different functions. The macrocell co= unt=20 > is maybe the best thing to look at when deciding whether the chip can do = the=20 > job. On the FGPA side, I think the Actel ProASIC3 15K gate has 128=20 > macrocells, whereas the Atmel AVF20V8B SPLD only has 300 gates equivalent= to=20 > 8 macrocells. > >> A CPLD with 64 or 72 macrocells may fulfill the OP's needs, and they can >> be found for around $1 to $3. > If this is the case then maybe the 15K gate, 128 macrocell Actel part (= =A32.77=20 > from Mouser) mentioned above may do okay, and requires no external memory= ..=20 > Also, once the tools are acquired and the hang got of them, then there is= a=20 > lot more power available later on. > Or use a CPLD of some sort as you say...=20 The Xilinx XC9572XL-10VQG64C is a 10ns 3.3V CPLD with 72 macrocells, 52 I/O pins in a TQFP-64 package and costs just $2.40 at Digikey. Altera's EPM3064ATC44-10N is a 10ns 3.3V CPLD with 64 macrocells, 34 I/Os in a TQFP-44, costs $2.55 There are faster models at a higher cost. I don't know the voltage the OP needs, but there are 5V versions available. Isaac __________________________________________________ Fale com seus amigos de gra=E7a com o novo Yahoo! Messenger=20 http://br.messenger.yahoo.com/=20 --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .