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-   -   Nokia drops RS-MMC(?) (https://talk.maemo.org/showthread.php?t=3161)

Serge 2006-10-05 17:33

Quote:

Originally Posted by SD69
The limitations of 770 in transferring file through MMC or USB interface is unfortunate. Remarkable that wireless is the fastest way to transfer a file.

Maybe it's a bit of offtopic, but what maximum speed did you observe with wireless interface? In my tests (using scp to copy files from/to device) it was never higher than 350-400kB/s, so it can't compete even with USB 1.1. Maybe that's because of some cryptography overhead, don't know. Ordinary USB wifi dongle used with desktop PC provides 2MB/s easily, so I thought that my wireless router is ok and it's Nokia 770 limiting files transfer performance. If it is not the case and wifi works much faster for you, I will have to investigate what's the problem. I also use WPA encryption here, what kind of encryption is used on your device?

SD69 2006-10-05 23:59

I have not measured my transfer rate on the 770 from my Linksys but I have not noticed that is any slower than my laptop, which got about 2Mbps last time I checked. Maybe something is wrong with your router or wireless setup? Check with other devices.

fanoush 2006-10-06 07:43

It is slow for me too. I thought it could be fast but never actually tried to measure it until yesterday. I remembered this post http://maemo.org/pipermail/maemo-dev...er/002189.html but forgot numbers so I was under impression that unencrypted speed is higher but looks like WPA performance improved since then so uencrypted setting doesn't help. I get 300-400Kb over ssh (wpa,aes+tkip setting on router). By changing ssh cipher from default 3des to blowfish, speed goes up by ~100kb.

I didn't try wget or ftp on device from local network or ftp server on n770 yet. But it looks like it is definitely slow. It is strange, the chip itself seem to allow real 48Mbit so who knows what part is slow, maybe again some clock setting? Or maybe the embedded arm9 cpu and the firmware.

The chip info is here
http://www.conexant.com/products/entry.jsp?id=375
but it probably uses other radio chip, according to this
https://garage.maemo.org/plugins/scm...=1&view=markup
my chip is in fact this one
http://www.st.com/stonline/products/...2/stlc4370.htm

both datasheets say
- Support for 54, 48, 36, 24, 18, 12, 9, and 6Mbps OFDM
- SPI serial host interface (up to 48Mbps)

Also in garage source there is mentioned also newer variant (3826.arm firmware) probably used in newer N770 devices. This chip is smaller but from datasheet parameters looks very similar. There is additional 4 bit sdio interface (so it can be used in SD wlan cards) but this interface it is probably not used in N770 anyway.

http://www.st.com/stonline/products/...3/stlc4550.htm

I guess it is slow and no one cares since you cannot detect it when downloading from interenet. Maybe the faster g speeds are there just to save power (radio is not transmitting/receiving so long).

SD69 2006-10-06 10:24

The poster tested download speed to MMC. Like you, I would guess any speed limitation is not due to radio chip, but from some interface somewhere in 770.

fanoush 2006-10-06 12:15

Quote:

Originally Posted by SD69
Interesting. How do you like it? It seems not even prudent to get card reader built-in to computer any more since it likely to have slower transfer speed than this device.

The card reader http://www.sharkoon.com/enghtml/usb.htm#xcplus arrived. I am quite happy. With my older 80x Transcend 1GB sd card it does 8MB/s on read while my other older card reader did only 3MB/s with same card.

With the 2GB Kingston MMCmobile it reads at very nice 14MB/s (dd test). File write to card in windows explorer was approx. 5MB/s (220MB in 2 files in 44 seconds)

Due to 2nd rows of pins and the doors the card insertion is slightly more complex but it is not an issue.

Final price with VAT was aprox. $11 (236CZK)

BanditRider 2006-10-11 23:58

I just received this i-rocks Portable USB Card Reader from Newegg for $12.99 US.

http://www.newegg.com/Product/Produc...82E16820308005

Informal testing shows it writes 2X faster and reads 5X faster than my old USB card reader. More formal testing to follow. My 2GB mmc-mobile card arrives tomorrow.


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