Hi All In case of PCB design it doesn't matter how many SDRAMs we install - the number of PCB layers is similar. The main factor that determines layer count is number of BGA balls - one simply need to make fan-out. So adding of one more chip does not increase the price - the chip can be not populated for particular application. There is one more advantage of new SoCs and FPGAs. In case of US+ family, the IOSERDES capabilities were extended and resembles now Rocket IO transceivers in Virtex 2 :) One can i.e. run 1000base-x on it or auto-tune the lane delay for fast serial ADC. They also support DDR4. I don't know if you are going to intensively use external DDR memory, but the DDR4 has a few nice benefits and much higher bandwidth. Greg
-----Original Message----- From: Slichter, Daniel H. (Fed) [mailto:daniel.slich...@nist.gov] Sent: Tuesday, April 12, 2016 3:56 AM To: Sébastien Bourdeauducq <s...@m-labs.hk>; Grzegorz Kasprowicz <kaspr...@gmail.com> Cc: 'Grzegorz Kasprowicz' <gkasp...@elka.pw.edu.pl>; artiq@lists.m-labs.hk Subject: RE: [ARTIQ] FW: initial specification of the project > On Saturday, 9 April 2016 6:10:36 PM HKT Grzegorz Kasprowicz wrote: > > Why do you think that CPUs have negative value? You don't have to > > use them at all. > > I already explained that the MPSoC has to be dealt with and cannot be > completely ignored. If we have two SDRAM systems, maybe we can to a > reasonable extent, but then it does complicate the board. On the DSP/"Sayma" boards, a hard SoC could have use for reducing the time it takes to perform feedback calculations (e.g. shifts of output signal frequency based on ADC readings). My comment in the previous email about "users" wanting this also pertains to the idea that people not using ARTIQ might want to buy these boards and use them for their own purposes. For many of them, having a hard SoC on board may make it faster/easier for them to get the boards doing what they want. Again, it's not totally necessary to have this but would enable more applications and a broader group of potentially interested customers. _______________________________________________ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
