RetroBrew Computers Forum
Discussion forum for the RetroBrew Computers community.
Home » RBC Forums » General Discussion » New 65C816 ECB SBC (New 65C816 ECB SBC)
New 65C816 ECB SBC [message #3375] Sun, 27 August 2017 10:52 Go to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
Greetings!

I have had this idea rattling around in my head for a 65816 ECB SBC for some time now -- and I had some free time on a family trip, so I put form to that thought. It is still in the routing optimizer, so I expect it will be some time before I order PCBs, but I thought I would share what I have. This is a first iteration, and it is the most complex thing I have designed to date -- and the first time I have incorporated GALs into my design. Therefore -- I don't expect it to work first time . . . Smile

The memory map is:

000000 - 007FFF On Board RAM
008000 - 008007 16550
008008 - 008008 RTC
008009 - 00801F Open for expansion
008020 - 0080FF Mapped to Z80 ports for ECB bus boards (IO)
008100 - 008FFF Open to ECB bus (RAM)
009000 - 00FFFF On board ROM
010000 - 017FFF Open to ECB bus (RAM)
018000 - 08FFFF On Board RAM
090000 - FFFFFF Open to ECB Bus

I have attached the schematic and the board(so far anyway) files along with a zip file(rename from piz) containing the source for the GALs.

I would appreciate any feedback!

Thanks,

Dan Werner

Report message to a moderator

Re: New 65C816 ECB SBC [message #3385 is a reply to message #3375] Tue, 29 August 2017 13:02 Go to previous messageGo to next message
rwiker is currently offline  rwiker
Messages: 14
Registered: February 2016
Junior Member
Interesting. Will that be useable as a single-board computer? What clock frequency are you going for?

Report message to a moderator

Re: New 65C816 ECB SBC [message #3386 is a reply to message #3385] Tue, 29 August 2017 13:21 Go to previous messageGo to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
Yes,should be (if it works) it has ROM/RAM and a serial port on board. There are no facilities for mass storage or no real I/O without using ECB though.

Report message to a moderator

Re: New 65C816 ECB SBC [message #3387 is a reply to message #3386] Tue, 29 August 2017 13:26 Go to previous messageGo to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
Sorry, posted too soon. Based on other SBCs, my guess is that clock speed will be limited by the ECB bus as there are no real provisions for IO wait states. The normal '816 operates at a max of 14Mhz @5v and I would hope to be able to hit that.

Report message to a moderator

Re: New 65C816 ECB SBC [message #3424 is a reply to message #3387] Wed, 06 September 2017 20:04 Go to previous messageGo to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
Quick update . . .

The boards are here. This is the second time I have used PCBWay, and I have to say I really like them. I ordered the boards on Saturday 9/2 and they arrived 9/6. (I ordered some of the parts that I am missing to complete the build -- they are not here yet . . . .Wink

I posted a pic of the partially populated board on the Wiki page.

Dan

Report message to a moderator

Re: New 65C816 ECB SBC [message #3479 is a reply to message #3424] Tue, 19 September 2017 19:42 Go to previous messageGo to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
Thanks to a MASSIVE amount of assistance from John Coffman (thanks John!Wink the 65816 SBC is working pretty well and we are drawing close to ordering a more final(ish) set of PCBs. The memory map has simplified some, but is not quite final yet -- we are looking at:


000000 - 007FFF On Board RAM
008000 - 00FDFF On Board RAM or ROM (depending on config setting) (TBD final ROM size Wink
00FE00 - 00FE06 16550
00FE07 - 00FE07 RTC/ ROM Size flag
00FE08 - 00FEFF Mapped to Z80 ports for ECB bus boards (IO)
00FF00 - 00FFFF On board ROM
010000 - 07FFFF On Board RAM
080000 - FFFFFF Open to ECB Bus RAM

We are still working out the details of the ROM size and selection. Once the final decisions are made, I will upload new schematics, GAL equations, and firmware to the wiki page.

Dan Werner

Report message to a moderator

Re: New 65C816 ECB SBC [message #3487 is a reply to message #3479] Thu, 21 September 2017 14:32 Go to previous messageGo to next message
etchedpixels is currently offline  etchedpixels
Messages: 333
Registered: October 2015
Senior Member
Like the fact that the low memory is now mostly RAM/ROM. For a lot of compiler stuff you can run much better and faster in the low 64K because the stack and the data are in the same bank so you only need 16bit pointers.

Report message to a moderator

Re: New 65C816 ECB SBC [message #3520 is a reply to message #3487] Sat, 23 September 2017 08:09 Go to previous messageGo to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
Maximizing RAM in the low 64K was one of John's many contributions to the project. You can select two modes by software (small/large), and you can set the size of the "small" mode in the GAL. Today the gal has options for an 8K or 16K "small size.

I put quite a bit of information on the wiki page, and will be posting the PCB files once it is done routing. I suspect I am only a few days from a PCB order.

Report message to a moderator

Re: New 65C816 ECB SBC [message #3522 is a reply to message #3520] Sun, 24 September 2017 10:37 Go to previous messageGo to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
The trace routing of the board is complete and boards have been ordered. We believe that this board should be reasonably error free, so I did order extras and will be offering them to anyone interested for $20. The schematic and board files are up to date on the wiki, and my contact information is on the board inventory page. I expect to have boards ready to go by 10/6.

Dan Werner

Report message to a moderator

Re: New 65C816 ECB SBC [message #3523 is a reply to message #3375] Sun, 24 September 2017 11:26 Go to previous messageGo to next message
w9gb is currently offline  w9gb
Messages: 55
Registered: October 2015
Location: Chicago, IL
Member
Appears to have Typo error on the schematic, 658C16 --> should be 65C816 ??

greg

Report message to a moderator

Re: New 65C816 ECB SBC [message #3524 is a reply to message #3523] Sun, 24 September 2017 11:59 Go to previous messageGo to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
Yup, that is a typo -- will correct and re-post

Report message to a moderator

Re: New 65C816 ECB SBC [message #3547 is a reply to message #3524] Thu, 28 September 2017 06:51 Go to previous messageGo to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
Tracking shows that boards will arrive tomorrow (Friday 9/29)

Report message to a moderator

Re: New 65C816 ECB SBC [message #3548 is a reply to message #3547] Thu, 28 September 2017 08:23 Go to previous messageGo to next message
rwiker is currently offline  rwiker
Messages: 14
Registered: February 2016
Junior Member
What clock speed did you achieve? Did you have to use wait states for the on-board memory?

Report message to a moderator

Re: New 65C816 ECB SBC [message #3549 is a reply to message #3548] Thu, 28 September 2017 09:53 Go to previous messageGo to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
There are no wait states. I have not spent any time trying higher clock speeds with the prototype board. There are many,many jumper wires on my prototype board and I am running a very slow eprom, so I never tried more then 2mHz. When the production boards and some new 29c256 rom chips all get here I will do a proper speed test. I have oscillators available up to 14mhz and have code running that will read/write from a floppy on the DISKIO V3 card, I should be able to get a very good idea how fast we can go.

Dan

Report message to a moderator

Re: New 65C816 ECB SBC [message #3550 is a reply to message #3549] Thu, 28 September 2017 09:56 Go to previous messageGo to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
Looks like John was able to get up to 5mhz with the prototype board (with all of the jumpers) and using fast 27SF512 70ns flash rom.

Report message to a moderator

Re: New 65C816 ECB SBC [message #3583 is a reply to message #3550] Fri, 06 October 2017 17:54 Go to previous messageGo to next message
danwerner is currently offline  danwerner
Messages: 50
Registered: October 2015
Member
I have one of the new V1 boards assembled and they seem to work well with no jumpers needed. I was able to get the board up to 4Mhz with a 90ns 29c256 ROM. The next higher osc I have is an 8mhz, and that did not work. At the moment I am running only 74LS (with one required 74HCT) so, with a faster ROM and a different logic family, your results may vary. I have a 70ns rom (SST27SF512) on the way, I will test with that chip once it arrives.

Report message to a moderator

Re: New 65C816 ECB SBC [message #4034 is a reply to message #3583] Mon, 01 January 2018 04:55 Go to previous message
etchedpixels is currently offline  etchedpixels
Messages: 333
Registered: October 2015
Senior Member
I've been playing with the software 65C816 emulation and getting Fuzix running on it as my tools and bench are still in storage (12 months into a 3 month renovation of a 150 year old house ;) Wink

One thing I kept hitting is that it's really hard to get good I/O performance on the 65C816 (much like the 6502), so while I could get a 4MHz Z80 to do SD Card transfers at 1 bye per 16 clocks (INI) and 250K/sec or so off an SD card. I couldn't get anywhere near that with the 65C816. Then I had an idea

If your logic maps FFxxyy to 00FExx or similar all of a sudden you've got the 65C816 MVN instruction and it goes down to 7 clocks per byte to move up to 256 bytes anywhere you want in the address space, which at least in simulation takes a 4MHZ 65C816 to a bit over 500K/second. In effect if you've got a window of memory mapping to the same I.O address you've got a built-in DMA engine and more than a five fold increase in performance.

Report message to a moderator

Previous Topic: multicomp IIc SD-CARD
Next Topic: Arc/Unarc For Dos/Windows 7

[ Syndicate this forum (XML) ] [ RSS ] [ PDF ]

Current Time: Fri Dec 12 01:17:33 PST 2025

Total time taken to generate the page: 0.03652 seconds
.:: Contact :: Home ::.

Powered by: FUDforum 3.0.9.
Copyright ©2001-2018 FUDforum Bulletin Board Software