Search found 730 matches

by Peter
Thu Jan 10, 2019 11:13 am
Forum: Hardware
Topic: FGPA Anyone?
Replies: 14
Views: 1114

Re: FGPA Anyone?

In the meantime a free scaler was released and another cycle accurate 68k core was revealed for another core, maybe I will try these one day. Are you referring to the FX68K core? I had a brief look, but was not in the mood to manually convert System Verilog to Verilog, which is required for my synt...
by Peter
Tue Jan 08, 2019 3:58 pm
Forum: Compatibles Corner
Topic: Q68 Ethernet
Replies: 18
Views: 804

Re: Q68 Ethernet

By the way, the CP2200 chip is well suitable for the QL, it has a directly compatible, 5V tolerant 8 bit bus interface. Should Q68 ethernet software be released, the QL can benefit.
by Peter
Tue Jan 08, 2019 3:46 pm
Forum: Compatibles Corner
Topic: Q68 Ethernet
Replies: 18
Views: 804

Re: Q68 Ethernet

Does the Q68 have any ethernet access? Or is anyone looking at providing ethernet access? Good and bad news. First the good news: Last summer I have already accessed the internet with the Q68 over ethernet. I successfully used ICMP ping, TCP echo, webserver, textmode webbrowser, POP3 email. This wa...
by Peter
Mon Dec 17, 2018 2:27 pm
Forum: Hardware
Topic: SGC successor brainstorming
Replies: 81
Views: 5544

Re: SGC successor brainstorming

Hi Tetroid,

thanks for your comments. Do you think it would be realistic to replace the PLD by a new one like the Lattice LC4128 or LC4256?

Peter
by Peter
Fri Dec 14, 2018 3:56 pm
Forum: Hardware
Topic: Q68 speed vs 680X0
Replies: 40
Views: 2559

Re: Q68 speed vs 680X0

If serialized mode is selected, the 68040 pipeline no longer allows read accesses to occur before completion of a write-back for a previous instruction. This is even less efficient than just turning off caches, so it should not surprise us.
by Peter
Fri Dec 07, 2018 9:51 pm
Forum: Hardware
Topic: Q68 speed vs 680X0
Replies: 40
Views: 2559

Re: Q68 speed vs 680X0

Silvester wrote:After blowing the dust of my Q40 I tried the benchmark program and got 54 seconds, which sounds OK for 40MHz 68040 against Peter's 80MHz 68060.

Could you try again after sending the COPYBACK command please?

Still quite a sensation for me that an SRAM based Q68 would beat a 68040 at same clock rate.
by Peter
Fri Dec 07, 2018 8:22 pm
Forum: Hardware
Topic: Q68 speed vs 680X0
Replies: 40
Views: 2559

Re: Q68 speed vs 680X0

After blowing the dust of my Q40 I tried the benchmark program and got 54 seconds, which sounds OK for 40MHz 68040 against Peter's 80MHz 68060. That was with CACHE_ON, with CACHE_OFF it was 167 seconds! That doesn't compare well with benchmark on my SGC: 176 seconds with CACHE_ON (212 with CACHE_OF...
by Peter
Fri Dec 07, 2018 8:06 pm
Forum: Hardware
Topic: Q68, QL-NET and I2C
Replies: 3
Views: 313

Re: Q68, QL-NET and I2C

I also remember reading that there is no support in the operating system for any kind of I2C communication (yet) and that the idea would be to "bitbang" those two registers at the correct speed and following the correct protocol to have a functioning bus. Fair enough, I can start working ...
by Peter
Wed Dec 05, 2018 11:49 am
Forum: Hardware
Topic: Q68 speed vs 680X0
Replies: 40
Views: 2559

Re: Q68 speed vs 680X0

As it happens I have 256k x 16 VRAM chips. One per board would satisfy the above mentioned spec. Can you tell which the part it is? Given that this option is intended for non SRAM access which can be of various kinds with different delays, some sort of 'DTACK' signal would have to be provided, basi...
by Peter
Sun Dec 02, 2018 9:09 pm
Forum: Hardware
Topic: Q68 speed vs 680X0
Replies: 40
Views: 2559

Re: Q68 speed vs 680X0

The main limit is the load the pins of the FPGA can drive, as this determines how many physical chips can be fitted, which in turn defines the maximum feasible amount of RAM, even if price was no object. The 68030 output voltages for the address lines are specified for 3.2 mA, while the FPGA specif...

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