Thanks Dennis, I gave up as its not listed on FTDI's summary product page...
Anyway, the FT232R datasheet says it can only do 7 or 8 data bits.
If that's so, this part will not work for lots of RS-485
networks that use 9-bit addressing...
IIRC Exar has parts that do this (but no Android drivers).
OP was not specific in his RS-485 requirement!
He might be best off building a small dongle
that does USB to the host with vanilla CDC,
with the dongle implementing the specific RS-485
protocol as he requires. This would allow
easier integration with hosts not able to meet
timing requirements etc; I've done similar...
Hope that helps,
Best Regards, Dave
Reply by ●September 11, 20142014-09-11
Dave Nadler <drn@nadler.com> wrote:
> The FT232R is missing from the product list on the FTDI web page.
On 09/10/2014 06:31 PM, edward.ming.lee@gmail.com wrote:
> On Wednesday, September 10, 2014 2:17:46 PM UTC-7, embdev-design wrote:
>> A typical RS232 to RS485 interface will switch the direction based on the slave side traffic, by default being listening to the master (tablet). It will switch back after a short delay (equivalent of 3 characters) after the slave ends the transmission. The speed affects only the 3 characters delay timer.
>
> But who's the master and who goes first? You don't necessary want to be the master just because you have a screen. You could be attaching as a slave or just a monitor station. There are lots of settings and interaction between your app, os and low-level driver. Configurations might depends on what app you are running. Working around Android might not be easy. Your work around could easily overwhelm whatever you gain from using the stock COTS Android.
>
> On Wednesday, September 10, 2014 4:30:19 PM UTC-4, Dennis wrote:
>> FDTI also makes an rs485 cable.
>> http://www.ftdichip.com/Support/Documents/DataSheets/Cables/DS_USB_RS485_CABLES.pdf
>
> The FTDI datasheet says this cable uses FT232R, and says:
> "The FT232R datasheet, DS_FT232R, is available at
> http://www.ftdichip.com."
>
> The link in the datasheet is broken.
> The FT232R is missing from the product list on the FTDI web page.
>
> Does this product exist?
> I was wondering if it was usable for RS-485 multi-drop;
> in particular, how does it handle direction-switching,
> addressing, and speed requirements...
No idea I have never done RS-485
>
> Anybody know if this is a viable solution?
>
> Thanks,
> Best Regards, Dave
>
Reply by ●September 10, 20142014-09-10
On Wednesday, September 10, 2014 2:17:46 PM UTC-7, embdev-design wrote:
> A typical RS232 to RS485 interface will switch the direction based on the slave side traffic, by default being listening to the master (tablet). It will switch back after a short delay (equivalent of 3 characters) after the slave ends the transmission. The speed affects only the 3 characters delay timer.
But who's the master and who goes first? You don't necessary want to be the master just because you have a screen. You could be attaching as a slave or just a monitor station. There are lots of settings and interaction between your app, os and low-level driver. Configurations might depends on what app you are running. Working around Android might not be easy. Your work around could easily overwhelm whatever you gain from using the stock COTS Android.
Reply by embdev-design●September 10, 20142014-09-10
A typical RS232 to RS485 interface will switch the direction based on the
slave side traffic, by default being listening to the master (tablet). It
will switch back after a short delay (equivalent of 3 characters) after the
slave ends the transmission. The speed affects only the 3 characters delay
timer.
Gabriel
>On Wednesday, September 10, 2014 4:30:19 PM UTC-4, Dennis wrote:
>> FDTI also makes an rs485 cable.
>>
>
>The FTDI datasheet says this cable uses FT232R, and says:
>"The FT232R datasheet, DS_FT232R, is available at
>http://www.ftdichip.com."
>
>The link in the datasheet is broken.
>The FT232R is missing from the product list on the FTDI web page.
>
>Does this product exist?
>I was wondering if it was usable for RS-485 multi-drop;
>in particular, how does it handle direction-switching,
>addressing, and speed requirements...
>
>Anybody know if this is a viable solution?
>
>Thanks,
>Best Regards, Dave
>
The FTDI datasheet says this cable uses FT232R, and says:
"The FT232R datasheet, DS_FT232R, is available at
http://www.ftdichip.com."
The link in the datasheet is broken.
The FT232R is missing from the product list on the FTDI web page.
Does this product exist?
I was wondering if it was usable for RS-485 multi-drop;
in particular, how does it handle direction-switching,
addressing, and speed requirements...
Anybody know if this is a viable solution?
Thanks,
Best Regards, Dave
Reply by Dennis●September 10, 20142014-09-10
Sorry to hijack this post but I am coming in late to this discussion..
On 09/10/2014 12:20 PM, embdev-design wrote:
> Hi pozz,
>
> Even a micro with no build in LCD controller will do the job if you do not
> need animation or other moving objects, and the system can be a industrial
> grade design. Not sure about the enclosure requirements, but a single board
> design can be achieved. We did a similar application with nice graphic and
> touch feedback, but in lower quantities.
>
> gabriel
>
>> Il 07/09/2014 00:38, edward.ming.lee@gmail.com ha scritto:
>>>>> I need a very low-cost (50USD for quantity) touch panel running
> Android OS. I'll use only the LCD, the touch panel and a serial interface
> (RS485). A USB device port (to make a connection with a PC) and/or USB
> host port (for connecting USB pen drives) would be nice. The size of LCD
> could be from 5 to 7".
>>>
>>>>> I don't need SD, Ethernet, WiFi, CAN, RTC, battery, Bluetooth and
> other
>>>
>>> Sound like you don't really need Android. You are spec'ing out
> everything that need Android/Linux/networking.
>>
>> But I need a LCD with a touch screen.
>>
>>
>>>>> The final application will be a HMI with good graphics and human
> interactions (like on Android smartphones).
>>>
>>> Or just a good micro with touch screen LCD.
>>
>> This is interesting. Do you think I could reach the same or similar
>> look&feel of Android without Android? Could you suggest an OS and
>> graphics frameworks or libraries to use? Mostly for touch management?
>>
>>
>>>> Do you think your price target is realistic? For $50 you will be hard
> pressed to find a small tablet which is about your specs minus the RS-485
> plus a few very low cost peripherals. I would think they way to go is to
> find the lowest priced tablet you can and add a USB RS-485 adapter.
>>>
>>> Might be doable if qty is high enough. I am thinking perhaps in 10K
> pcs.
>>>
>>
>> Yes, the quantity will be about 5k/10k.
>>
I just bought a "Landfill Ready" low end Android for $43.04 at the local
Staples. The link is here
http://www.staples.com/Nobis-7-inch-8GB-Tablet/product_1052513#pr-header-back-to-top-link
It comes with an OTG cable so that the USB port can be used in host mode.
FDTI now provides Android drivers for their chips, see
http://www.ftdichip.com/Android.htm
As a proof of concept exercise I downloaded the FDTI serial terminal app
from the Google store.This uses the Android driver mentioned above. I
then attached a FDTI TTL-232R-3.3 cable between the Android and my
Beaglebone Black serial console header. Fired up the FDTI serial
terminal on the Android and reset the Beaglebone and got the Beaglebone
startup display on my new Android.
FDTI also makes an rs485 cable.
http://www.ftdichip.com/Support/Documents/DataSheets/Cables/DS_USB_RS485_CABLES.pdf
At unit prices it is a bit above your $50, but in quantity I suspect it
would be in your range - maybe do your own adapter using the FDTI chip
to get exactly the features you need.
Since this would use generic support you would be less dependent on a
particular Android model/supplier.
Reply by embdev-design●September 10, 20142014-09-10
Hi pozz,
Even a micro with no build in LCD controller will do the job if you do not
need animation or other moving objects, and the system can be a industrial
grade design. Not sure about the enclosure requirements, but a single board
design can be achieved. We did a similar application with nice graphic and
touch feedback, but in lower quantities.
gabriel
>Il 07/09/2014 00:38, edward.ming.lee@gmail.com ha scritto:
>>>> I need a very low-cost (50USD for quantity) touch panel running
Android OS. I'll use only the LCD, the touch panel and a serial interface
(RS485). A USB device port (to make a connection with a PC) and/or USB
host port (for connecting USB pen drives) would be nice. The size of LCD
could be from 5 to 7".
>>
>>>> I don't need SD, Ethernet, WiFi, CAN, RTC, battery, Bluetooth and
other
>>
>> Sound like you don't really need Android. You are spec'ing out
everything that need Android/Linux/networking.
>
>But I need a LCD with a touch screen.
>
>
>>>> The final application will be a HMI with good graphics and human
interactions (like on Android smartphones).
>>
>> Or just a good micro with touch screen LCD.
>
>This is interesting. Do you think I could reach the same or similar
>look&feel of Android without Android? Could you suggest an OS and
>graphics frameworks or libraries to use? Mostly for touch management?
>
>
>>> Do you think your price target is realistic? For $50 you will be hard
pressed to find a small tablet which is about your specs minus the RS-485
plus a few very low cost peripherals. I would think they way to go is to
find the lowest priced tablet you can and add a USB RS-485 adapter.
>>
>> Might be doable if qty is high enough. I am thinking perhaps in 10K
> I could use just Linux and abandon the idea to use Android, but the
> question will be: is it possible to create the same or a similar
> look&feel with bare Linux? ...without spending too much time to reinvent
> and rewrite the same things already written in Android OS?