steveh@tasman.cc.utas.edu.au (Steven Howell) (04/30/91)
Evening folks. I have a small, well large actually, problem that needs some attention. I was curious if some of you programming pro's could help me out on this one. We have just overhauled a system design and updated it. However a few elements had to be axed due to their speed/age etc. One of those replaced was 4 SY6551 Serial controller chips. Me, (Steveh), being the hardware man , i decided to replace these controllers with two Z8530 serial SCC chips. The same as those used in Macs and Suns. However, the programmer has doubted the chip, since there are too many register to keep track of via firmware, but I still want this chip employed. Could someone PLEASE give me an example of how the registers would be set up for a simple comms example. Eg. say i wanted to; Txd 9600 data bits 8 stop bits 1 parity none dtr enabled xon/xoff enabled transmit Unlimited at these settings, just to get the thing up and going. What would the 14 write registers and 7 read register look like. How would they be programmed for just that task, and too ignore all this sldc and other extra functions. Thanks in advance steve h
steveh@tasman.cc.utas.edu.au (Steven Howell) (05/06/91)
Thanks to those people who offered advice on the Zilog 8530 SCC chip. I have sifted thru all the info supplied, and finally came to a conclusion. Yes, the chip is cheap, its does come in a PLCC package, and is fairly popular, with routines already written, But according to people experienced with this chip, they generally disagree that the chip is a good device to program. Due to the ammount of registers, the number of lines of code just to set it up, the fact that you can not read the status of the write registers, made the firmware programmer take an axe to my idea of employing the chip. I now am back to were i started from. In need a four or 2 port serial controller chip. The SCC chips i have implimented in the past have been Motorola's MC6850 and the MC6551/SY6551. Both good in performance, but do not cover the entire baud rate range, and the 6850 requires external baud rate generator. (not to mention they only support one channel without multiplexting). anyway, since i have been threatened with excruciating pain by my programmer if i employ the Z8530, It looks like i am back on the market for a SCC. Can anybody reccommend a device that can do the job. The problem is, i am not that educated in the firmware side of things, therefor makes it hard for me to understand the programming point of view. thanks in advance. steve h
jclark@sdcc6.ucsd.edu (John Clark) (05/07/91)
In article <steveh.673492219@tasman> steveh@tasman.cc.utas.edu.au (Steven Howell) writes:
+
+I now am back to were i started from. In need a four or 2 port serial
+controller chip.
Have you looked at the Signetics 269x chip. It has 'directly'
available registers, a few 'quirks', does 'Async' only. If you don't
need synchronous then it might be a solution.
One 'problem' is that one interrupt serves all. So software must
read a register to learn that a data byte has been received or a
parity error detected, etc.
Another is it has a baud rate table, two to be exact so one has to
select which table and which entry, the maximum in either is 38.4K.
The Zilog/AMD 8530 allows 1 Meg in some configs and versions(85300
or something like that).
--
John Clark
jclark@ucsd.eduDXB132@psuvm.psu.edu (05/09/91)
In article <steveh.673492219@tasman>, steveh@tasman.cc.utas.edu.au (Steven Howell) says: >I now am back to were i started from. In need a four or 2 port serial >controller chip. >The SCC chips i have implimented in the past have been Motorola's MC6850 >and the MC6551/SY6551. (Rockwell) In that case you might want to check out the 65C52...it's basically a two-port version of the 6551 with perhaps some extra features. (I have docs on the 65C52 but not the 6551). I wrote a driver for it (Amiga) and it's easy to program. The only glitch I encountered was that hardware CTS handshaking can't be disasbled. -- Dan Babcock
steveh@tasman.cc.utas.edu.au (Steven Howell) (05/10/91)
I have found a replacement. Its a 65c52 from Rockwell. Its is identical to the 6551, but has two ports. This chip is very simple to program, co-operative and well damn priced. Has its own on chip baud generator and is controlled by a few registers. If Only they had a SMD version... anyway thanks to all those who replied. I am glad I managed to get first hand news on the Zilog 8530 before attempting to impliment it. thanks steve h