April 2013 - Bluetooth-dev - lists.apple.com

Re: A2DP with AAC codec: non-existent document reference in the "Bluetooth Accessory Design Guidelines for Apple Products"
by John Westing 11 Apr '13

11 Apr '13

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Re: data transmission rate...to slow...
by Etan Kissling 11 Apr '13

11 Apr '13

Frederic, there is only one packet of up to ~20 bytes transmitted every two connection events if you use reliable data transfer. If you want to increase that to ~ four packets every connection event, you have to use unreliable data transfer (WriteWithoutResponse / Notification) and have to add reliability in your app layer. Note that WiFi interferes with BLE, disabling it should net you a small boost in throughput. These are the throughputs I could achieve with iPhone as central and dedicated peripheral: http://www.scriptreactor.com/conn_interval-throughput.pdf Etan On 11.04.2013, at 14:54, Frederic Visticot <fvisticot(a)gmail.com> wrote: > I have made some tests to exchange data between 2 iDevices (iOS6 iPad3/iPhone5) using CBPeripheralManagerConnectionLatencyLow settings. > > The maximum rate I have is 1135 bytes / s (1.1KB/s) > > - Is it possible to get better speed ? > - What is the maximum I can have with iOS stack ? > > From some documents: > BLE: 200kbits/s -> 25KB/s > NFC: 424kbits/s > > Why is the difference so huge (20x slower) ? > > Fred > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/bluetooth-dev/kissling%40oberon.ch > > This email sent to kissling(a)oberon.ch _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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data transmission rate...to slow...
by Frederic Visticot 11 Apr '13

11 Apr '13

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BT accessory
by Leonardo Martínez 10 Apr '13

10 Apr '13

_______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com Hi All, We are thinking of make an accessory. It is a medical device that must run for 8 hours generating sounds defined by some parameters. In order to change them the patient males a VOIP with the doctor and then the doctor updates them in real time. The patient must ack that the new parameters are ok. Then, the connection finishes and the patient turns off the BT connection. We have discarded audio streaming due to have better battery perfomance. Could i implement SPP and HFP at the same time? If not, is it possible to implement a low level BT programming on the devices mentioned? Thanks!

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Re: A2DP with AAC codec: non-existent document reference in the "Bluetooth Accessory Design Guidelines for Apple Products"
by John Westing 09 Apr '13

09 Apr '13

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Re: UUID across Factory Reset
by Etan Kissling 08 Apr '13

08 Apr '13

Yes, you cannot connect to a device that was previously known after a factory reset. There's just no way to do that currently on iOS. Etan On 08.04.2013, at 16:52, Ram Jayaraman <ram(a)milesense.com> wrote: > Hi Etan, > > My concern is the other way around. I _would_ like to connect to the > same devices after a factory reset or for that matter a software > update using some mechanism instead of trying to scan for new > peripherals again. I am guessing that the iOS UUIDs are not a Mac > address hash and are actually generated UUIDs. > > Ram > > > On Apr 8, 2013, at 4:24, Etan Kissling <kissling(a)oberon.ch> wrote: > >> Ram, >> >> No, there is no such mechanism in iOS up to 6.1.3+. >> >> - Reset all Settings is enough to clear the UUID cache, you don't have to go >> through the whole Erase All Content and Settings process. >> >> - Reset Network Settings is not enough. >> >> Etan >> >> >> On 04.04.2013, at 04:00, Ram Jayaraman <ram(a)milesense.com> wrote: >> >>> I am assuming the UUID cache of BTLE devices will be wiped when I do a factory reset of the iPhone. Is there a mechanism to connect to the peripherals again based on their public macs or any other mechanism which can avoid a re-scan ? >>> >>> Ram _______________________________________________ >>> Do not post admin requests to the list. They will be ignored. >>> Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) >>> Help/Unsubscribe/Update your Subscription: >>> https://lists.apple.com/mailman/options/bluetooth-dev/kissling%40oberon.ch >>> >>> This email sent to kissling(a)oberon.ch >> _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: data loss when trying to transfer large data with BLE
by Etan Kissling 08 Apr '13

08 Apr '13

Rene, With WriteWithResponse, you can send one write request per two connection events. This is because only one WriteWithResponse can be active at a time, and because the acknowledge packet is usually sent with the proceeding connection event, as it can not be prepared in the few microseconds of time to send it in the same packet. With WriteWithoutResponse, packets will get dropped, but you can send about 4 (officially 6) of them per connection event (and have to do the acknowledgments yourself, if your use case requires a reliable stream. Syncing your writes is not necessary with the CBCentralManager. I did not run into problems queueing up large amounts of data on the iOS side. If you still want to sync WriteWithResponse calls with the connection event, you can use the didWriteCharacteristic callback. Etan On 08.04.2013, at 16:42, Rene Limberger <rl(a)favionics.com> wrote: > I have a use case that needs to exchange data packets of ~60bytes between an iOS device and a peripheral at as high of a data rate as possible. I understand that BLE is not designed to do that but i would like to evaluate what speeds we could get. > > To give some background, i am using a BLE112 module from Bluegiga in BGApi mode. For testing, the module is connected to a mac with a usb-to-serial adapter. The interface is 9600 baud with hardware flow control (RTS/CTS). I wrote a mac application that, using the BGAPI calls, controls the BLE stack on the module. I have also written a iOS app that scans for the peripheral, connects to it, find the services and characteristics. This all "sort of works" but when im trying to write to the attributes at a very high rate, eventually, data is lost, the module locks up and the connection is lost. > > Im trying to understand where the issue is, in iOS, the module, or both and what i can do about it. Specifically, i have read previous discussions on this list that talk about high data rates and understand that others have run into this. It would be interesting to hear how you solved this. > > One thing i have read repeatedly is that "the writes on iOS should be sync'd to the connection interval"? From my limited understanding of BLE, i gather than there is only a limited amount of data that can be exchanged per connection event. If so, how much data is that and how do i sync my writes to that on iOS? Is there a way when a connection interval occurs and how much data it transferred so i can write the next data? > > As mentioned above, my data packets are ~60bytes, so given the max length of an attribute of 20b, i created 3 attributes, with 20b each and another attribute which indicates he length (as my private protocol packets are variable length). When writing these 3 20b values and the 1b length, the initial 20 or so writes come thru to the peripheral just fine. but then things start to slow down and eventually all data is lost and the connection drops. > > As others have mentioned, the writes should be throttled, but im just not clear on what they should be throttled to? > > Thanks in advance, > -r > > > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/bluetooth-dev/kissling%40oberon.ch > > This email sent to kissling(a)oberon.ch _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: UUID across Factory Reset
by Ram Jayaraman 08 Apr '13

08 Apr '13

Hi Etan, My concern is the other way around. I _would_ like to connect to the same devices after a factory reset or for that matter a software update using some mechanism instead of trying to scan for new peripherals again. I am guessing that the iOS UUIDs are not a Mac address hash and are actually generated UUIDs. Ram On Apr 8, 2013, at 4:24, Etan Kissling <kissling(a)oberon.ch> wrote: > Ram, > > No, there is no such mechanism in iOS up to 6.1.3+. > > - Reset all Settings is enough to clear the UUID cache, you don't have to go > through the whole Erase All Content and Settings process. > > - Reset Network Settings is not enough. > > Etan > > > On 04.04.2013, at 04:00, Ram Jayaraman <ram(a)milesense.com> wrote: > >> I am assuming the UUID cache of BTLE devices will be wiped when I do a factory reset of the iPhone. Is there a mechanism to connect to the peripherals again based on their public macs or any other mechanism which can avoid a re-scan ? >> >> Ram _______________________________________________ >> Do not post admin requests to the list. They will be ignored. >> Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) >> Help/Unsubscribe/Update your Subscription: >> https://lists.apple.com/mailman/options/bluetooth-dev/kissling%40oberon.ch >> >> This email sent to kissling(a)oberon.ch > _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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data loss when trying to transfer large data with BLE
by Rene Limberger 08 Apr '13

08 Apr '13

I have a use case that needs to exchange data packets of ~60bytes between an iOS device and a peripheral at as high of a data rate as possible. I understand that BLE is not designed to do that but i would like to evaluate what speeds we could get. To give some background, i am using a BLE112 module from Bluegiga in BGApi mode. For testing, the module is connected to a mac with a usb-to-serial adapter. The interface is 9600 baud with hardware flow control (RTS/CTS). I wrote a mac application that, using the BGAPI calls, controls the BLE stack on the module. I have also written a iOS app that scans for the peripheral, connects to it, find the services and characteristics. This all "sort of works" but when im trying to write to the attributes at a very high rate, eventually, data is lost, the module locks up and the connection is lost. Im trying to understand where the issue is, in iOS, the module, or both and what i can do about it. Specifically, i have read previous discussions on this list that talk about high data rates and understand that others have run into this. It would be interesting to hear how you solved this. One thing i have read repeatedly is that "the writes on iOS should be sync'd to the connection interval"? From my limited understanding of BLE, i gather than there is only a limited amount of data that can be exchanged per connection event. If so, how much data is that and how do i sync my writes to that on iOS? Is there a way when a connection interval occurs and how much data it transferred so i can write the next data? As mentioned above, my data packets are ~60bytes, so given the max length of an attribute of 20b, i created 3 attributes, with 20b each and another attribute which indicates he length (as my private protocol packets are variable length). When writing these 3 20b values and the 1b length, the initial 20 or so writes come thru to the peripheral just fine. but then things start to slow down and eventually all data is lost and the connection drops. As others have mentioned, the writes should be throttled, but im just not clear on what they should be throttled to? Thanks in advance, -r _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: UUID across Factory Reset
by Etan Kissling 08 Apr '13

08 Apr '13

Ram, No, there is no such mechanism in iOS up to 6.1.3+. - Reset all Settings is enough to clear the UUID cache, you don't have to go through the whole Erase All Content and Settings process. - Reset Network Settings is not enough. Etan On 04.04.2013, at 04:00, Ram Jayaraman <ram(a)milesense.com> wrote: > I am assuming the UUID cache of BTLE devices will be wiped when I do a factory reset of the iPhone. Is there a mechanism to connect to the peripherals again based on their public macs or any other mechanism which can avoid a re-scan ? > > Ram _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/bluetooth-dev/kissling%40oberon.ch > > This email sent to kissling(a)oberon.ch _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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