[Milkymist-devel] New schematics online

[Sébastien Bourdeauducq]

Hi,

On Friday 12 February 2010 03:57:48 Adam Wang wrote:
> According to this, a summary listed for change logs:
> 1). Deleted: Ethernet -- R39 10K to set COL/RMII,

Yes, Ethernet is now used in MII mode (instead of RMII as in the previous 
version) to enable compatibility with a broader set of Ethernet MACs on the 
FPGA side and allow quick testing of the PCB using the (bloated but 
functional) OpenCores Ethernet MAC.

>             Misc. -- J19 microSD socket, this is RIGHT ANGLE SMT type;
> Do you think our T-push uSD socket[1] with card insert detect in
> Inventory you can use?

I suggest we keep the current connector. I have chosen it because it opens on 
the top, allowing it to be placed anywhere on the board to change the uSD 
card. Since the MM1 board has a lot of connectors, board perimeter is a scarce 
resource, and I do not expect the uSD card to be changed very often (the board 
already has USB and Ethernet to transfer files).

I forgot to say: for the case, I'm thinking of having a small door similar to 
what the EeePC has to change the RAM module and the SSD [1]. This door could 
also give access to JTAG and RS232. So, if we go for this option, place these 
parts accordingly.

> >  * if layout allows, adding of an expansion connector with some FPGA
> > spare I/Os
> 
> Yes, this will be determined after placement.

If possible, also connect D8-D15 + BYTE# of the NOR flash in order to increase 
bandwidth. This Flash is used to configure the FPGA and boot the system 
(provide bootloader + Linux kernel + filesystem), and higher bandwidth means 
faster boot. Since the Flash is also used to configure the FPGA, these signals 
must be connected to pre-determined FPGA pins (see UG380 "Spartan-6 FPGA 
Configuration User Guide", p. 46).

Thanks,
Sébastien

[1] http://www.youtube.com/watch?v=2VXQY_-V860