| Andy Peters 09/20/11 11:13 Read: 191 times Tucson, Az USA |
#183816 - pedantry, again Responding to: Richard Erlacher's previous message |
Richard Erlacher said:
The one advantage of the CPLD over the FPGA, now making the distinction, is that, once programmed, the CPLD doesn't require it be programmed under system power each time the power is turned on. There are some FPGA families which have onboard non-volatile configuration storage with "instant" configuration, meaning that as soon as power is stable the FPGA is configured. Actel's flash parts work this way. There are also OTP FPGAs (QuickLogic, Actel) which are also ready as soon as power is stable. The real difference between a CPLD and an FPGA is that of resources. A CPLD macrocell has a much wider combinatorial logic resource in front of its (single) register than an FPGA's slice. An FPGA's slice may have one, two or even four registers and a simpler (3-, 4- or 6-input) combinatorial lookup table. FPGAs also have significantly greater routing resources than CPLDs, which is necessary if you need wide muxes and such. Timing in a CPLD is simpler to analyze because the paths are simpler and delays fairly constant, but that's not really interesting any more since you do your FPGA design, set a clock period constraint, and let the tools have at it and they'll tell you if you win or not. -a |
| Topic | Author | Date |
| Bit-configurable transceiver chips | Per Westermark | 09/12/11 02:28 |
| Suggesting....again... | Michael Karas | 09/12/11 05:35 |
| Alas 5V needed and ribbon cables are a bit "rough" | Per Westermark | 09/12/11 06:54 |
| Another Suggestion.... | Michael Karas | 09/12/11 05:59 |
| level translator | Jan Waclawek | 09/12/11 06:21 |
| Alas, "weak output drive" and no input hysterese | Per Westermark | 09/12/11 07:30 |
| TI sn74gtl2010 | Stefan KAnev | 09/17/11 02:18 |
| or NXP GTL2010,GTL2000 | Stefan KAnev | 09/19/11 01:24 |
| looks promising | Richard Erlacher | 09/21/11 22:29 |
| NXP GTL20xx -> NVT20xx | Jan Waclawek | 10/04/11 00:57 |
| Need to read more to understand them | Per Westermark | 09/20/11 02:04 |
| looks like the cat's miauw | Erik Malund | 09/21/11 07:45 |
| NXP has .... | Erik Malund | 09/12/11 13:28 |
| I2C or SPI just can't get even close to the huge bandwidth | Per Westermark | 09/12/11 14:01 |
| nope, no I²C clocks | Erik Malund | 09/12/11 14:21 |
| extender, not expander | Per Westermark | 09/12/11 14:37 |
| I have been wondering this myself | Justin Fontes | 09/12/11 16:18 |
| Supported capacitance seems to be the snag | Per Westermark | 09/12/11 17:23 |
| Differential SPI | Jez Smith | 09/16/11 09:39 |
| Serial -> buffers on adapter boards is a potential solution | Per Westermark | 09/16/11 14:41 |
| Have you considered programmable logic? | Richard Erlacher | 09/19/11 14:08 |
| I had suggested this as well | Michael Karas | 09/19/11 14:33 |
| Yes ... I remember that ... | Richard Erlacher | 09/19/11 23:43 |
| Long life | Per Westermark | 09/20/11 01:59 |
| They seem to live a long time ... | Richard Erlacher | 09/20/11 09:22 |
| Adapters | Per Westermark | 09/20/11 10:16 |
| These aren't necessarily so "huge" | Richard Erlacher | 09/20/11 19:52 |
| Not huge in size | Per Westermark | 09/21/11 01:49 |
| Some of them can handle that. | Richard Erlacher | 09/21/11 22:34 |
| Yes and no | Per Westermark | 09/22/11 04:53 |
| There are ways ... | Richard Erlacher | 09/22/11 10:55 |
| Body diodes | Per Westermark | 09/22/11 16:39 |
| serial termination ... | Erik Malund | 09/23/11 07:36 |
| Yes, current- and bandwidth-limiting components used | Per Westermark | 09/23/11 08:25 |
| you youing whippersnappers, pay attention | Erik Malund | 09/23/11 11:45 |
| pedantry, again | Andy Peters | 09/20/11 11:13 |
| What would YOU suggest? | Richard Erlacher | 09/20/11 19:45 |
| Here's a thought ... | Richard Erlacher | 10/17/11 03:03 |
| Probably | Per Westermark | 10/17/11 15:51 |
I'd sugest you consider older CPLD's | Richard Erlacher | 10/17/11 19:14 |



