> Does anyone have an advice what type of CPLD could be used to implement > both CIAs and PLA replacement? As I am rather newbie to those, I would like > to clarify also whether code done for e.g. Chameleon or other projects which > implemented CIAs already could be reused without problems? I assume it > depends only (?) on the chip's capabilities/IO pins count and not really on > the brand/type? On 2012-09-02, at 02:42, André Fachat wrote: > It depends much on how much extra stuff you want to have in your design. Basically a single-chip replacement for those three chips. Since there is no analogue stuff in those, they should (uneducated belief) be relatively easy to implement. > I'm mostly thinking about 5V/3.3V issues. 5V devices are hard to come by these days. I read there are some 3.3, which are supposed to be compatible with 5V circuits but - yes - I have no experience with any of those. > > Then you have to check the size. The most restricted part is a flip-flop in a CPLD, basically a single register bit. If you look at the CIA, it has at least 16 register bits per port (data + direction), i.e. 32, plus 16 bit latch plus 16 bit counter per timer (IIRC), then there are the shift register, control registers, and internal state bits... So that's way more than 100 bits. > The largest Xilinx 95xx CPLD is the 95108 with 108 so-called cells, with one flip flop per cell (IIRC) - a CIA would not fit in there. A PLA would probably fit into a much smaller CPLD, as it does not use flip-flops. Here the I/O pins are the restriction. > > You speak about "both CIAs and PLA" - do you plan to put it into one programmable device? That's what I thought of. I wanted to save some space and power consumption and those three seem (to me) to be the best candidates to be placed into a programmable device. > Then I guess you'd need a small FPGA anyway. Since I have no preference (n00b in both) it can be FPGA too. Just thought if CPLD could do the trick as I'd expect it to be cheaper. > Another question is the development environment. One reason I chose Xilinx for my design for example was because the webpack IDE is free and runs on Linux as well. Very good point! > BTW: a good way to start the development (i.e. before trying to solder those SMD chips yourself, is to get some CPLD or FPGA modules with DIL outlines, like here: http://shop.trenz-electronic.de/catalog/default.php?cPath=1_48&osCsid=992a0cbc43ac0c33617a30e302ab7fc3 Another one. Yes, I was thinking of some adapters but there seem to be ready-made modules. -- SD! Message was sent through the cbm-hackers mailing listReceived on 2012-09-02 02:00:09
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