Ides of March Status of X16

[DragonGaulois]

On 3/22/2022 at 3:46 PM, AndyMt said:

That's what a SD-2-IEC device does - which already exist. Maybe not super fast, but they will work.

oh, ok sorry,

thanks for your answer

[TomXP411]

On 3/22/2022 at 7:46 AM, AndyMt said:

That's what a SD-2-IEC device does - which already exist. Maybe not super fast, but they will work.

Just for clarity's sake, the device's name is "SD2IEC". No hyphens.

Normally, it's no big deal what you want to call it, but using different names for the same thing makes it hard to search the forums, since searching for "sd2iec" may not turn up references to "sd-2-iec".

[kelli217]

I'm pretty sure AndyMt wrote it like that to emphasize the SD-to-IEC aspect of it, and break it down for clarity to someone who might have thought it was just an 'XL2000'... numbers and letters that sound cool. Or maybe a vanity name for Stephen Douglas's second IEC device.

But yeah, the actual product is just SD2IEC.

[BruceMcF]

On 3/22/2022 at 10:46 AM, AndyMt said:

That's what a SD-2-IEC device does - which already exist. Maybe not super fast, but they will work.

And adding the C128/1571/1581 burst mode should certainly be do-able, because it's a three wire interface with data, clock, and a receiver "ACK" line, so it's not based on a fixed clock speed, but goes as fast as the slower of the sender and receiver. It uses the IEC SRQ line as the burst mode clock line, and the IEC clock line as the burst mode ACK line.

If the VIA timers and serial shift register lines from the CX16 are used, the CX16 ought to support a pretty high top speed for burst mode.

And of course, it's just used for bulk data transfers, using the normal IEC for thinks like opening files, etc. ... so starting with an SD2IEC which already has that side covered makes sense.

[Scott Robison]

Just to be clear, I think what we're all talking about is "fast serial mode" not "burst mode". Burst mode is above and beyond fast serial mode, and can support even faster speeds than fast serial alone.

[TomXP411]

On 3/22/2022 at 5:28 PM, Scott Robison said:

Just to be clear, I think what we're all talking about is "fast serial mode" not "burst mode". Burst mode is above and beyond fast serial mode, and can support even faster speeds than fast serial alone.

Maybe? Now I need to go re-read the 1581 manual... 

The answer is "why not both?" From the 1581 manual: 

Quote

 



INTRODUCTION



The Commodore 1581 is a versatile 3.5" disk drive that can be used with a variety of computers, including the COMMODORE 128™,the COMMODORE 64®, the Plus 4™, COMMODORE 16™, and VIC 20.™



Also, in addition to the convenience of 3.5" disks, the 1581 offers the following features:

• 
  Standard and fast serial data transfer rates—The 1581 automatically selects the proper data transfer rate (fast or slow) to match the operating modes available on the Commodore 128computer.
  


• 
  Double-sided, double-density MFM data recording—Provides more than 800K formatted storage capacity per disk (400K +per side).
  


• 
  Special high-speed burst commands—These commands, used for machine language programs, transfer data several times faster than the standard or fast serial rates
  

 

So ideally, we'd support 1MHz fast serial and burst modes on the 1571 and 1581, plus a 4x and 8x version for SD2IEC devices based on faster ARM devices, like the Pi based boards we've been discussing.

 

[Scott Robison]

On 3/22/2022 at 7:07 PM, TomXP411 said:

Maybe? Now I need to go re-read the 1581 manual... 



The answer is "why not both?" From the 1581 manual: 



So ideally, we'd support 1MHz fast serial and burst modes on the 1571 and 1581, plus a 4x and 8x version for SD2IEC devices based on faster ARM devices, like the Pi based boards we've been discussing.

That is a good answer. The burst commands require extra programming on the part of software as I understand it, whereas fast serial "just works". But people have been conflating the two for a long time. I did until working on the 128 recently.

[Travis Bryant moore]

What is that like adding a maximite 2 board for the cx16? As an accelerator card seconary processor to cary the load of larger programs like an operating system? Though the maximite board may be better for the SD card?

[BruceMcF]

On 3/22/2022 at 8:28 PM, Scott Robison said:

Just to be clear, I think what we're all talking about is "fast serial mode" not "burst mode". Burst mode is above and beyond fast serial mode, and can support even faster speeds than fast serial alone.

i am talking about this one: Burst Fastloader for C64 // Fast Serial for µIEC. AFAIU, whether using the fast serial protocol a byte at a time for "fast serial mode" or for multiple bytes at a time for "burst mode", it's based on the the same protocol, using the SRQ line as the serial clock line and the conventional IEC clock line as the ACK line.

As far as modifying the SD2IEC firmware to work with the 1571 burst mode, it seems like it's already been done, which is one of the best kinds of projects to take on.

[Scott Robison]

On 3/23/2022 at 3:54 PM, BruceMcF said:

i am talking about this one: Burst Fastloader for C64 // Fast Serial for µIEC. AFAIU, whether using the fast serial protocol a byte at a time for "fast serial mode" or for multiple bytes at a time for "burst mode", it's based on the the same protocol, using the SRQ line as the serial clock line and the conventional IEC clock line as the ACK line.



As far as modifying the SD2IEC firmware to work with the 1571 burst mode, it seems like it's already been done, which is one of the best kinds of projects to take on.

Right, burst mode builds on fast serial with its SRQ line, but it works automatically with the kernal routines. Burst mode commands can go even faster but requires special commands to be sent over the command channel.

Sorry, probably being too pedantic.