Date: Tue, 21 Oct 1997 13:01:42 -0700 From: Marcio Saito <marcio@cyclades.com> To: dg@root.com, support@freebsd.com Cc: cy_serial@cyclades.com, John Lima <johnl@cyclades.com> Subject: Changes in the Cyclades Cyclom-Y. Message-ID: <344D0A26.75720A8B@cyclades.com>
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David Greenman: I'm writing to let you know about some changes coming for the Cyclom-Y boards (that will require a few small changes on the Cyclom-Y driver) and to see how we can work this out so that our common users can still count on full support from FreeBSD for the Cyclades products. As a matter of fact, these changes will affect any board based on the Cirrus Logic CD1400 serial processor (I believe you support other CD1400-based cards). Cirrus Logic is closing the factory that manufactures the CD1400 rev G (the one being used today). Starting this month, they will provide only the CD1400 rev I. Cyclades has enough parts to sell until mid-98, but we will have to change to the new chip. We are in process of re-layouting the boards and, starting in December for some models, we will be shipping a new hardware version of the Cyclom-Y boards. The transition will be complete by March of 98. The CD1400 is 100% software compatible but, unfortunatelly, it is not pin-compatible. So, we need to redesign the board. There are two HW changes that affect Software: 1) The new CD1400 run at 60 MHz (against 25MHz used today). That makes it faster and allow baud rates up to 230kbps. In SW, we need to change the baud rate divisor tables (registers RCOR, RBPR, TCOR and TBPR) and the PPR register initialization to account for the change in the clock. 2) You are probably familiar with the fact that the CD1400 can do automatic reception HW flow control (drop a modem control signal signal when the reception FIFO is getting full and the driver doesn't empty it fast enough). Unfortunatelly, the CD1400 do that using the pin labeled as DTR, which makes it not very useful with V.34 modems. Since we are re-layouting the board, we are also inverting DTR and RTS in HW (connecting the CD1400 pin labeled DTR to the RTS connector pin and vice versa), so that we can take advantage of this CD1400 feature. Because of that, the driver has to be changed to reverse the meaning of RTS and DTR (basically, swap the accesses to the MSVR1 and MSVR2 registers) for the new boards. Since the SW can identify the new boards and swap the DTR/RTS handling by itself, the HW change is transparent to users (no special cables needed). Because we want the driver to support both and even mix old and new cards, we need a per-port flag in the driver that says whether the port is in a new or old card. This flag defines the baud-rate divider values to be loaded and the correct treatment of DTR and RTS. The flag is set for each port at initialization time based on the CD1400 version ID (GFRCR register). Any revision number prior to and including 0x46 (rev G) should use the old baud rate table and original DTR/RTS handling. Any version above 0x46 (the rev I is 0x48) should use the new scheme, support 230kbps, revert DTR and RTS and, optionally, take advantage of the on-chip HW flow control to avoid FIFO overflows. As I said above, the new boards will start to come out already in mid-December (Cyclom-8Yo). In February/98, the Cyclom-8Ys and the Cyclom-Ye (16-port modules) will be changed. By April, we should complete the transition with the 8-port external modules. As you can see from the explanation above, the changes are very localized and simple. Until now, FreeBSD has been developing and maintaining the driver. We can provide CD1400 documentation (even though, besides what I listed above, there are no changes that affect SW), code fragments, support and actual HW prototype units for test and validation. It is Cyclades interest to have the drivers updated as soon as possible (if possible, before December comes). I would like to get some feedback from you in terms of how you prefer to conduct the changes. If necessary and appropriated, we could even get the latest driver version from you, execute and validate the changes and give it back to you within a few days. In that case I would ask you to send us the latest revision of the driver files and give us an idea of the FreeBSD release schedule so that we can get it done early enough. Please give us some feedback and acknolowdge the receipt of this message. Thanks in advance for your time. Regards, Marcio. _____________________________________________________________________ Marcio Saito Product Manager/Dir. of Technology mailto:marcio@cyclades.com - voice: 510-770-9727 x214 Cyclades Corporation - http://www.cyclades.com _____________________________________________________________________
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