Author Topic: Albireo - USB/SD/Serial interface for CPC (Read 65728 times)

skywalky · « **Reply #25 on:** 21:41, 19 October 15 »

@PulkoMandy, one for me, please.

Jungsi · « **Reply #26 on:** 21:50, 19 October 15 »

I'll take also one please! :-)

Poliander · « **Reply #27 on:** 21:52, 19 October 15 »

I'm also in for one, please.

yannis_uno · « **Reply #28 on:** 21:58, 19 October 15 »

Count me in for 1 please, thanks!

Rennert · « **Reply #29 on:** 21:58, 19 October 15 »

I buy 1 board please

PulkoMandy · « **Reply #30 on:** 22:40, 19 October 15 »

Some precisions since I get some questions by PM (don't be shy, share your questions here so everyone can get the answers!)

There is no software available for this board currently
What you buy is only the hardware. You will have to write your own drivers for it or wait for someone to provide support (as a tool loadable from disk, a ROM, etc). While I have started some work on a ROM, I make no promises or guarantee that I will get that to work, and if I do, when it will be made available.

What will be possible with appropriate software
Some people will want to use it to load games from it. Remember that it is not a floppy emulator. This means, anything accessing the floppy disk without going through the AMSDOS system ROM, will not load.
Anything that uses AMSDOS, but initializes only ROM 7 or ignores the current drive setting, will not work.

The ROM will also use some memory for itself, which can also create some issues. It's possible to keep the RAM use quite low, but still some bytes will be used at least to store the new RSXs from the ROM.

BASIC programs should not be a problem, more complex software may need some patching. To get an idea, the games with 1 or 2 blue dots listed here will most likely work: http://cngsoft.no-ip.org/cpc_lzx.htm . The one with red dots will not (this is for the unprotected games).

What will be possible without a ROM
If you don't have a ROM expansion already (RamCard, Rom Board, MegaFlash, FlashGordon, X-Mem or similar), this board can still be used with software running in RAM. In that case, the software must be loaded from disk or tape - no autoboot support! The software will of course use some memory for itself, which possibly means even more compatibility problems if you want to use it as a game loader.

I don't plan to provide this kind of software, at all - because I don't need it myself. If someone else decides to attempt it, I can provide support, hints and technical documentation (writing the programming docs and examples is higher on my TODO list than writing the software).

HAL 6128 · « **Reply #31 on:** 23:02, 19 October 15 »

...count me for another one!

PulkoMandy · « **Reply #32 on:** 23:12, 19 October 15 »

Current waiting list

0 - PulkoMandy
1 - OffseT
2 - TFM (x2 - what's up with people ordering two devices? do you use that much CPC to need two boards?)
4 - ||C||-||E||
5 - majikeyric (x2)
7 - CraigsBar (x2)
9 - pelrun
10 - Optimus
11 - AsT
12 - Gryzor
13 - hsimpson
14 - SOS
15 - tonio8bits (x2)
17 - Audronic
18 - gros_minet
19 - Fessor
20 - Sykobee (Briggsy)
21 - skywalky
22 - Jungsi
23 - Poliander
24 - Yannis_uno
25 - Rennert
26 - HAL6128

I have updated the first post with the info from my replies, so they don't get lost in the flow of preorders (already 27 boards to assemble! This will keep me busy during the winter at least)

CraigsBar · « **Reply #33 on:** 23:13, 19 October 15 »

Quote from: PulkoMandy on 21:23, 19 October 15

Current waiting list
0 - PulkoMandy
1 - OffseT
2 - TFM (x2 - what's up with people ordering two devices? do you use that much CPC to need two boards?)
4 - ||C||-||E||
5 - majikeyric (x2)
7 - CraigsBar (x2)
9 - pelrun
10 - Optimus
11 - AsT
12 - Gryzor
13 - hsimpson
14 - SOS
15 - tonio8bits (x2)
17 - Audronic
18 - gros_minet
Power supply
There was a question about the power supply required for the board. It needs 5V, and the power consumption is around:
Glue logic - 20mA
CH376S - 30mA
TL16C550D - 10mA
FT230X - 8.3mA
Total: 69mA, to which you need to add power for an SD card (30 to 100mA depending on the model chosen) and/or USB devices.

Well my 2 are as follows... 1 for the cpc's easily accessible and interchangeable. The other one will be lost, hidden and embedded in my just CPC tower.

Joseman · « **Reply #34 on:** 01:40, 20 October 15 »

1 for me too please!!

Tai · « **Reply #35 on:** 01:50, 20 October 15 »

Please, count me in for 1 board!

Grim · « **Reply #36 on:** 06:58, 20 October 15 »

+1 board, thanx.

A few more questions:

What's the maximum capacity of the SD card the CH376 can handle? (I haven't looked at the datasheet yet)
Does the announced transfer speed (128K snapshot loaded in 0.83s) theoretical or factual? (HOLYSHIFT! 0.83s?! :)
Do you accept payment in rum bottles?

PulkoMandy · « **Reply #37 on:** 08:21, 20 October 15 »

Max. Storage size

~~The datasheet doesn't give any limit for the SD card size. It is FAT32, so there is a limit of one partition of 2TB~~. I did my tests with an USB drive of 2GB and it seems to be working for now. I'm not sure how much space we need to fit the complete CPC software collection?

[edit]
After checking the chinese website of WCH, there is a size limit of "only" 32GB. It does support SDHC cards to allow this. I don't know if a larger drive can be used on USB, I'll have to test that.

Serial speed

For now everything about the serial interface is theoretical - I only drawn the schematics for it. Here is the math:

The serial controller gets a 24MHz clock
It divides this by 16 internally, to get a 1.5MHz clock
It sends/receives 1 bit per clock cycle, so 1.5Mbaud
Sending a byte needs 8 data bits + 1 start bit + 1 stop bit, so 0.150 MB/s or 150 KB/s

Is it reachable in real world conditions? On the hardware level, one difficult thing at such high speed on a serial link is keeping the two sides synchronized. This is why the USB adapter is integrated on the board: this way, the USB adapter and the serial controller run on the exact same clock. There is no way they can get out of sync.

On the software level, the z80 will be the limiting factor. Well optimized code could achieve this speed. To help the z80, there are a few features on the board:

Buffers: in the UART controller, a 16 byte buffer. In the USB controller, a 512 byte buffer.
Hardware flow control: The PC does not need to wait for the CPC to read the bytes. It can send 512 bytes at a time and wait for them to be written, without risk of a byte getting lost because the z80 was doing something else.
Interrupts: I don't know yet if this will be useful, the z80 can get an interrupt when the receive buffer is nearly full. This means there is no need to poll the serial port to wait for new bytes, just HALT and wait. The interrupt can also be NMI, in that case the gate array interrupts won't cause any interference (you can run in DI mode).
Short serial link: the actual serial link is only a few centimeters long on the board itself, this will limit the risk of data corruption. The rest of the connection is USB, which has strong protection features (CRC) and will get the data safely to the other side. Error checks on the z80 side or checksumming are thus not needed, and explicit acknowledge may not be needed either.

Everything else for the maximal speed is in the hands of people writing the z80 code. Can you write a loop tight enough to run this fast?

reidrac · « **Reply #38 on:** 10:36, 20 October 15 »

I'd love to have one board, if that's possible. Thanks!

fastofruto · « **Reply #39 on:** 11:16, 20 October 15 »

Hi! One for me please!

cosa_nostra-6128 · « **Reply #40 on:** 13:27, 20 October 15 »

Hi! One for me please!,thank very much

Targhan · « **Reply #41 on:** 13:49, 20 October 15 »

I think I want one too! Thanks!

oratyper · « **Reply #42 on:** 14:07, 20 October 15 »

Hello, one for me please

Thanks

NiNxPe · « **Reply #43 on:** 16:08, 20 October 15 »

+1 plz

TFM · « **Reply #44 on:** 17:33, 20 October 15 »

Quote from: PulkoMandy on 08:21, 20 October 15

Max. Storage size

After checking the chinese website of WCH, there is a size limit of "only" 32GB. It does support SDHC cards to allow this. I don't know if a larger drive can be used on USB, I'll have to test that.

In the datasheet V1.0 I found (for chip version &41) the limit the size in general to 32 GB due to the file-system IIRC.

Quote from: PulkoMandy on 08:21, 20 October 15

Interrupts: I don't know yet if this will be useful, the z80 can get an interrupt when the receive buffer is nearly full.

Such an interrupt would be a great feature, because it's desirable it the CPU can do something else than data transfer in parallel.

The datasheet is written in bad english, have to browse through it again to find out how to select and load files. But there maybe a better source of information out there in the net.

PulkoMandy · « **Reply #45 on:** 18:01, 20 October 15 »

CH376 programming resources

Yes, there are some resources that are helpful to better understand the datasheet.
The CooCox driver was helpful: CooCox provides free and open-source CH376 USB disk and SD card file management
My early WIP code for the AMSDOS compatible filesystem ROM: cpctools/resources/CH376 at master · cpcsdk/cpctools · GitHub The file ch376.i has description of all the commands in a more compact form, but not all the details. It should give a good overview of how things work. It includes only the FS commands for now, not the USB low level ones.
Current waiting list

0 - PulkoMandy
1 - OffseT
2 - TFM (x2 - what's up with people ordering two devices? do you use that much CPC to need two boards?)
4 - ||C||-||E||
5 - majikeyric (x2)
7 - CraigsBar (x2)
9 - pelrun
10 - Optimus
11 - AsT
12 - Gryzor
13 - hsimpson
14 - SOS
15 - tonio8bits (x2)
17 - Audronic
18 - gros_minet
19 - Fessor
20 - Sykobee (Briggsy)
21 - skywalky
22 - Jungsi
23 - Poliander
24 - Yannis_uno
25 - Rennert
26 - HAL6128
27 - Joseman
28 - Tai
29 - Grim
30 - reidrac
31 - cosa_nostra_6128
32 - Targhan
33 - oratyper
34 - NiNxPe

Latest design changes
I'm still refining the routing. Today changes:

USB device (serial link) connector moved to the side of the board, instead of the top. This will make the cable less annoying when it is plugged
Replaced the jumpers for configuration with a DIP switch

fgbrain · « **Reply #46 on:** 23:15, 20 October 15 »

Hi!

Will it be possible to connect and use USB printers or mice??
That would be great! But then one USB port is not enough

Vandalsk · « **Reply #47 on:** 23:38, 20 October 15 »

Please, count me for 2 boards please! Thanks.

TFM · « **Reply #48 on:** 23:50, 20 October 15 »

Netter Avatar!

PulkoMandy · « **Reply #49 on:** 00:18, 21 October 15 »

Quote from: fgbrain on 23:15, 20 October 15

Hi!

Will it be possible to connect and use USB printers or mice??
That would be great! But then one USB port is not enough

Hi,
"Connecting" is of course possible. Getting them to actually do something, however...

More seriously, the controller chip can also handle some other USB devices, as far as I can tell anything HID should not be a problem. However, it is then acting as a simple USB controller, which means the CPC will have to do some work: reading the HID reports as they come on the wire, parsing them (the format is fairly simple), and moving the mouse cursor on screen, of course.

For printers, I have no idea if this would work. It depends on the printer, the interface it exposes and how hard it is for the CPC to generate the data to send to it.

You can read the datasheet for CH375 if you want to get a more precise idea of how the chip works for this.

CH376: usb mass storage / sd card FAT32
CH375: usb host for other kind of devices
CH372: usb device (for plugging the CPC as a "slave" device to another computer - this will probably not be used, by me at least)

The CH376 is compatible with 375 and 372 and is programmed the same way for the relevant parts.

News:

Author Topic: Albireo - USB/SD/Serial interface for CPC (Read 65728 times)