Hello again everyone, Further progress on the FCDEV3B: the people at Technotronix (the assembly shop I'm going to use) got back to me and said that pcbcart's proposed panelization is OK. I relayed this approval to pcbcart, and pcbcart folks said that they are now starting production. Finally! If we go by the 20 working days lead time we paid for, the PCBs should be back some time in the second half of March.
On the BGA reballing front, the bubble mailer with the parts, a check and some accompanying order notes will go out to the reballing company on Tuesday, Feb 21 - this Saturday will be the soonest I can put it together on my end, but the postal service here won't be open until the following Tuesday. The BGA reballing company's terms say 3 weeks turnaround time after the receipt of the order and all materials, so again we are looking at late March for everything to come back. I now need to work on preparing the serial cable. When we get the boards populated with parts and power them up (I already have the power cable which I made back in 2015 for powering the historical souvenir TI D-Sample board we've got - our FCDEV3B has the same DC power input connector as TI's historical development boards), the very first thing we'll need will be the Calypso UART connection for talking to the Calypso internal boot ROM, hence I need to make the necessary preparations. Our FCDEV3B has a 5x2 pin header on which both Calypso UARTs are brought out without any level shifters - 2.8V native, but everyone else connects 3.3V signals to them, hence we'll do likewise. My plan has been all along to use an off-the-shelf FT2232 board as the serial interface for our FCDEV3B. FT2232 is a USB to dual UART adapter, i.e., a single USB device turns into two UARTs; there are FT2232D and FT2232H variants. There are many vendors who make FT2232D or FT2232H breakout boards; these boards provide a USB mini-B connector for PC/laptop connection on one side and all FT2232 user interface signals brought out to header pins on the other side. The adapter I plan on using myself is an FT2232D board from PLDkit (http://pldkit.com/other/ft2232d-module), I have a couple of them on hand already, but to other people who are going to get FCDEV3B boards eventually, feel free to use whichever adapter you like - your preferences don't have to be the same as mine. But how will the FCDEV3B connect to the FT2232 breakout board? I plan on making a special cable as follows: * Main body of the cable: flat ribbon cable with 10 conductors of the multicolor kind, standard wire colors going BROYGBVGWB from pin 1 to pin 10; * On the FCDEV3B end, crimp a 5x2 pin IDC female receptacle onto the ribbon cable, to mate with the 5x2 pin header on the board; * On the FT2232 breakout board end, split the ribbon cable into 10 individual wires and terminate each wire onto a single-pin female socket that mates with a single discrete male header pin. Using a chart of which wire color corresponds to which UART signal, manually connect the individual female pin sockets to the header pins on the breakout board. The above solution is not perfect by any means, but it is the best I can currently think of without building our own custom FT2232 adapter board. Building a custom FreeCalypso USB-serial adapter board is something we can definitely do in the future, but in the short term we need a quicker solution, hence my cable hack outlined above. Right now I need to scrounge up all of the necessary materials for making this cable, and I am hoping to have one cable made before the PCBs and the reballed BGAs come back. The PCBs are panelized with 4 boards per panel; unless something changes, my current plan is to do the first assembly run on two panels, thus we'll have 8 boards in the very first batch. I will need to test all 8 boards, but I should be able to do it with just one serial cable and just one FT2232 adapter board - I'll be testing the 8 FCDEV3B boards sequentially, not simultaneously, so I'll just unplug the cable from one board and plug it into the next. Then later when it's time to ship boards to other community members and to those who have claimed theirs through crowdfunding contribution, I will need to make more of these serial cables so we'll be able to include one with each shipped board. We have enough parts for a total of 20 boards, and the OSP finish on the SMT pads on the PCB has a limited shelf life, so we'll need to have all 20 boards assembled fairly soon-ish, but I plan on doing a split build of first 8 boards (2 panels), then the other 12 boards (3 panels) in order to reduce the risk of loss to bad parts or population mistakes. Exciting times ahead - stay tuned! Mychaela aka The Mother _______________________________________________ Community mailing list [email protected] https://www.freecalypso.org/mailman/listinfo/community
