Group, Well, I need to choose between XC3S50 and EPM1270. Both have pros and cons. I list them below, and I'd like to ask you to point out other important issues, and which would you choose if you were me.
My circuit occupies around 50% of XC3S50 or EPM1270. I might need several tens of the chips finally, But at this point I just need 1-3 for the prototype. I am aming at TQ144 package. It needs to interface 5V TTL logic. I plan to use 3.3V LVT244/245 to shift the voltage for inputs. I didn't check 5V/2.5V voltage shifters. My circuit is slow, working with 20MHz clock.
XC3S50 pros:
- Pin compatible SC3S200 available for possible growth
- Cheap (+ for XC3S50, + for XC3S200 at XILINX online store)
- RAM on chip. Good if I want to add a small FIFO in the future cons:
- Don't know where to buy XCF01S configuration flash. cost?
- Needs both 2.5V and 3.3V power supply to interface 3.3V logic
EPM1270 pros:
- On chip configuration flash
- On chip user flash, if I want to store some bits in the future
- Need only single 3.3V power supply to interface 3.3V logic cons:
- expensive (EPM1270C5ES + at digikey). May cost more for none-ES? (for example, EPM1270C3 costs )
- No TQ144 pin compatible bigger chips
cheers, vax, 9000