STE V2 BOOSTER + SRAM STATUS ( ABANDONED 2017)

[exxos]

Will the ATTINY store in its flash and copy to sram when booting, and then any changes made during regular use & reset will only touch the sram?

The ATTINY is being used as a flash register, so it will store the settings until changed..

Reason for asking is that my use for the 8/32MHz register would be to run devpac and compiling in 32MHz and switch to 8MHz when launching the code. Rewriting the flash all the time will quickly wear it out ...

True I was only actually thinking about people selecting things like ROM and not actually wanting to do it 100,000+ times

Saying that, there was a bit of trickery involved with all this... Because basically the CPU writes to the PLD internal registers, and writes the values to the ATTINY at the same time.

I guess I could use another data line direct from the CPU as a switch line to actually only update the PLD register, or the ATTINY register..

So maybe use data line 9, if high then write to the ATTINY (will also write to the PLD internal latches), and when low, just update the PLD internal latches... This way you can actually configure the booster on/off without having to write to the ATTINY each time

(This of course puts additional requirements on the clock cycle change to be made crash-safe which might be too difficult .. ?)

I don't follow you there I think...

The 32MHz/8MHz switch can generally happen at any time... If you looked at the CPU clock signal on the scope, you would see it changing between 32MHz and 8MHz constantly anyway...

[troed]

So maybe use data line 9, if high then write to the ATTINY (will also write to the PLD internal latches), and when low, just update the PLD internal latches... This way you can actually configure the booster on/off without having to write to the ATTINY each time

Sounds like a plan if possible

(This of course puts additional requirements on the clock cycle change to be made crash-safe which might be too difficult .. ?)

I don't follow you there I think...

The 32MHz/8MHz switch can generally happen at any time... If you looked at the CPU clock signal on the scope, you would see it changing between 32MHz and 8MHz constantly anyway...

Heh, disregard. I wasn't really thinking about that you already do that indeed

/Troed

[Smonson]

Let me know if you need code written for the attiny, I've used them a lot over the years. BTW, you can get attinys in SOIC-8, e.g. attiny25 which has 128 bytes EEPROM and 2K of flash.

[ube]

It’s all Done. More or less.

[exxos]

Let me know if you need code written for the attiny, I've used them a lot over the years. BTW, you can get attinys in SOIC-8, e.g. attiny25 which has 128 bytes EEPROM and 2K of flash.

Thanks, hopefully Urban has sorted it out

Having to use a 14pin ATTINY as I need 8bit IO with a couple of control lines.

[Smonson]

Cool

[TheNameOfTheGame]

Is there going to be any way to adjust the processor speed like 8, 16, 24, 32Mhz?

Some games run too fast at 32Mhz but too slow at 8. 16Mhz sometimes is the best for them.

[exxos]

Is there going to be any way to adjust the processor speed like 8, 16, 24, 32Mhz?

Some games run too fast at 32Mhz but too slow at 8. 16Mhz sometimes is the best for them.

What games run to fast ? Mostly 32mhz only pushes about 25% max speed because of the st ram bottleneck.

[TheNameOfTheGame]

Hmmm, maybe it is from running in an emulator at 32Mhz then. I tried the same game Doodlebug on my T28 on real hardware and it ran really good.

[exxos]

Hmmm, maybe it is from running in an emulator at 32Mhz then. I tried the same game Doodlebug on my T28 on real hardware and it ran really good.

Steem for example, 32 MHz runs entire emulation four times faster. In the real world, you cannot accelerate ST-RAM speeds and it remains 100%.

ROM speeds run at around 300% at 32MHz, the CPU can run at full speed along with the ROM. In terms of ram, this cannot be accelerated runs at 100%. In terms of games the majority of game speed is dependent on ram access speed. This is why you only mostly see speedups with 3-D games as they use a lot of int-div type maths functions which the CPU can run at 32Mhz. Though unfortunately, reading and writing the values slow it down no end so you only end up with about 25% speed boost overall.

In terms of GEM and desktop stuff /apps, which heavily rely on ROM , this runs a lot faster the CPU spends more time accessing ROM and RAM. Of course it really depends on instructions and code being run. The raw speed of ROM access is about 300%, technically it should be 400%, but of course some of the test loop has to run in RAM which slows it all down.

If the same test was done with ram running at 200% speed, then the ROM access speed would be 300% + 100% about due to faster ram access. The ROM itself does not actually run any faster, but the coach testing the loop doors as it partly runs in ST-RAM. Again if it ST ram run at double speed again you would get, 300% +100% +100% = 500%. Again this does not mean ROM actually runs at this speed but this is what the benchmark will show. Of course the loop runs faster overall, so it is not like the benchmarks are inaccurate.

As for the T28, assuming this has cache ? Then ST-RAM in parts are running in the cache RAM at 28Mhz. So some instruction loops get accelerated a lot. In this respect, this is why the 030 CPU is better, as it is a more efficient core, and has data and instruction caches which can run very fast. Though of course a side effect of this is that things start have compatibility issues with the new CPU etc.

The work I am doing, is to keep everything using a 68000 core and to max it out as much as possible. This will keep compatibility to a maximum, of course things like demos or any code is timing dependent isn't going to work. That is the price you pay for extra speed.