ST72681 usb 2.0 high-speed 8-bit mcu flash drive controller

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ag123
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ST72681 usb 2.0 high-speed 8-bit mcu flash drive controller

Post by ag123 »

during my googling i stumbled into this rather odd sku (apparently from ST)
http://www.bdtic.com/ST/ST72681.html
https://www.arrow.com/en/products/st726 ... lectronics

it is an 8 bits ! flash memory controller which sports a usb 2.0 high speed mass storage interface. I'd think it would be necessary to flash that firmware into the st7 chip. but as usual what is interesting is the usb 2.0 high speed interface 480 Mbps. accordingly the specs says it can transfer at 10 MB per secs.

it supports certain flash memory skus so I ventured to look at one of them
https://www.alldatasheet.com/view.jsp?S ... d=K9F1G08U

it would seem like an unorthodox way to get usb 2.0 high speeds, by speaking 'flash memory' to the flash controller
but there may be other issues like firmware etc for the st7 chip etc

it seemed there are some pieces floating around but it is marked as an obsolete part
https://www.aliexpress.com/wholesale?ca ... t=+ST72681
ag123
Posts: 707
Joined: Thu Dec 19, 2019 5:30 am
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Re: ST72681 usb 2.0 high-speed 8-bit mcu flash drive controller

Post by ag123 »

this would be pretty much similar to those cypress fx2 based chips
https://sigrok.org/wiki/Fx2grok

https://sigrok.org/wiki/Lcsoft_Mini_Board
https://www.aliexpress.com/wholesale?ca ... CY7C68013A

i'm not too sure if there may possibly be something similar from ST with this approach

of course the more 'formal' way is to use one of those sku that has the ulpi high speed interface and a transceiver.
that'd be the most robust and flexible way to get true usb 2.0 high speeds, it'd take getting down to the details as i think the ulpi interface runs at 60 mhz which probably means that the components would likely need to run on a single pcb rather than lose wires

ulpi with wires as a module is also avaliable but kind of pricier and a key question would be if the lose wires would corrupt signals at 60mhz
https://www.aliexpress.com/wholesale?ca ... xt=usb3300
ag123
Posts: 707
Joined: Thu Dec 19, 2019 5:30 am
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Re: ST72681 usb 2.0 high-speed 8-bit mcu flash drive controller

Post by ag123 »

i found another unorthodox way to get usb2.0 high speed - FT2232
https://www.ftdichip.com/Support/Docume ... T2232H.pdf

https://www.aliexpress.com/wholesale?ca ... ext=ft2232
this is quite commonly used for some programmers (e.g. jtag/swd) and is possibly more flexible than the cypress fx2 for interfacing
they are also kind of pricy but that i think FT2232 are quite widely supported by desktop software

found yet another slightly cheaper one from FTDI FT232H
https://www.ftdichip.com/Support/Docume ... FT232H.pdf
https://www.aliexpress.com/wholesale?ca ... ext=ft232h
zoomx
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Re: ST72681 usb 2.0 high-speed 8-bit mcu flash drive controller

Post by zoomx »

ag123 wrote:
Thu Nov 05, 2020 6:03 pm
during my googling i stumbled into this rather odd sku (apparently from ST)
http://www.bdtic.com/ST/ST72681.html
https://www.arrow.com/en/products/st726 ... lectronics
You found the ST7 MCU family, about 2000-2005 era.
There was also ST9 family and ST6, I used them many many years ago in assembly. ST6 was common in Italy because a magazine, Nuova Elettronica, published many articles about it.
ag123
Posts: 707
Joined: Thu Dec 19, 2019 5:30 am
Answers: 3

Re: ST72681 usb 2.0 high-speed 8-bit mcu flash drive controller

Post by ag123 »

the thing that gets somewhat interesting is the usb high speed interface despite a st7 8 bit mcu.
the better way to get usb high speeds is to use a ulpi transceiver with stm32, this would give true usb high speeds with any intended protocols.
but some of the ulpi usb high speed transceivers aren't all that commonly distributed as do the stm32 mcus

one of those usb high speed transceivers that is purported to work is usb3300 from microchip
https://ww1.microchip.com/downloads/en/ ... 01783C.pdf
https://www.aliexpress.com/wholesale?ca ... xt=usb3300

however, that still requires stm32 mcus which sports the ulpi pins and interfaces. hence, i started searching for 'alternatives' for casual usb high speed interfacing. it'd seem FT232H and FT2232H would be the simplest given the common support and drivers on the desktop side.
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