MIDI BLE Example NRF52DK

RE: MIDI BLE Example NRF52DK

Mohammad Afaneh — Fri, 30 Jun 2017 03:44:48 GMT

I recently wrote a blog post that addresses this implementation. A reader on my blog asked the same question about implementing BLE MIDI on nRF52, and he also pointed me to the official spec (referenced in the blog post).

The post is way too long to include here so here's the link if this is something people are looking for. The post also includes the full source code. I'm thinking I will post it on GitHub as well sometime soon.

Bluetooth GATT: Custom Services and Characteristics [MIDI use case]

Hope this helps.

RE: MIDI BLE Example NRF52DK

Remo — Thu, 09 Feb 2017 15:52:08 GMT

Many thanks for your answers

RE: MIDI BLE Example NRF52DK

Stian Røed Hafskjold — Thu, 09 Feb 2017 12:20:17 GMT

7.5ms is the minimum interval according to the BLE standard. But, this is also decided by the central device. E.g. iphone does not support shorter intervals than 30ms (except for HID)

RE: MIDI BLE Example NRF52DK

Remo — Mon, 06 Feb 2017 18:43:47 GMT

Is it on a NRF51 faster? Or is this 7.5ms an BLE standard

RE: MIDI BLE Example NRF52DK

Stian Røed Hafskjold — Mon, 06 Feb 2017 17:55:41 GMT

No. 7.5ms is the fastest. So if you want greater accuracy than this, I think you would have to add a time stamp in the MIDI messages.

RE: MIDI BLE Example NRF52DK

Remo — Mon, 06 Feb 2017 17:03:11 GMT

Question: is it possible to get this 7.5 ms value faster (1-2 ms) ?

RE: MIDI BLE Example NRF52DK

Remo — Mon, 06 Feb 2017 15:29:41 GMT

Oh wow, yes this is much better. Now i need to find out how i can made it with 1ms latency. For this will the midi BLE send an time Stamp. Many thanks Stian

RE: MIDI BLE Example NRF52DK

Stian Røed Hafskjold — Mon, 06 Feb 2017 12:00:35 GMT

What is the connection interval you are using? If the connection interval is 20 ms and you send a sample every 100ms, maybe some of the samples are arriving to late, and is pushed over to the next connection interval? You can try to set the connection interval to 7.5 ms which is the shortest according to the BLE spec.

RE: MIDI BLE Example NRF52DK

Remo — Sun, 05 Feb 2017 11:13:48 GMT

Long time ago i work on the issue. Now i have an stable working MIDI BLE communication. But i issue i cant find out. When i Play an midi File from (iMac or iOS or anything) the Play is not time stable. I try to explain. When i send every 100ms an Drum Sound as Example. so is every 5to10 Sounds an delay of exact 20ms. I hope someone can help me. I use the Keil SDK with the s132_nrf52_3.1.0 Softdevice

RE: MIDI BLE Example NRF52DK

Stian Røed Hafskjold — Mon, 12 Dec 2016 10:15:30 GMT

Also, are you using nRF52 or nRF51? nRF51 requires a different Softdevice (s130) and you need to open the examples in the pca10028 folder. Which development kit are you using?

RE: MIDI BLE Example NRF52DK

Stian Røed Hafskjold — Mon, 12 Dec 2016 10:14:09 GMT

Which version of the SDK are you using? SDK version 12.x.0 uses SoftDevice 3.0.0, and version 11.0.0 uses SoftDevice 2.0.x. The ble_app_uart example is working out of the box. Please follow the instructions here: infocenter.nordicsemi.com/.../ble_sdk_app_nus_eval.html.

Examples in the ble_peripheral folder requires the SoftDevice, and examples in the peripheral folder does not require the SoftDevice. Do a full chip erase in nRFgo Studio before you flash the non-SD examples.

How do you know that the example is not running? The BLE examples are also blinking a LED to show that they are advertising.

Are you using Keil to compile and flash the examples? Have you configured the debugger correctly in Keil? Got to Options->Debug, Use: JLink. Go to Settings and choose the right debugger, and SWD interface.

RE: MIDI BLE Example NRF52DK

Remo — Fri, 02 Dec 2016 15:37:28 GMT

OK i load the softdevice 3.0.0 with the nRFgo Studio. Then i open an example and get an error.....

Error: Flash Download failed - "Cortex-M4"

RE: MIDI BLE Example NRF52DK

Stian Røed Hafskjold — Fri, 02 Dec 2016 09:42:41 GMT

infocenter.nordicsemi.com/.../getting_started_softdevice.html

RE: MIDI BLE Example NRF52DK

Remo — Thu, 01 Dec 2016 16:02:40 GMT

I drag the nrf52832_xxaa.hex file to the JLINK Folder. After this the LED Flash smoth.

RE: MIDI BLE Example NRF52DK

Stian Røed Hafskjold — Thu, 01 Dec 2016 11:44:38 GMT

Have you programmed the SoftDevice first when using the BLE examples? All the BLE examples need the BLE stack (SoftDevice).

RE: MIDI BLE Example NRF52DK

Remo — Thu, 01 Dec 2016 09:17:38 GMT

...mmmh... now i found something bad News. I Need to go backt to start. i find out, only the blinky examples works on my board. all other BLE examples in KEIL works not. I can compile -> download, but the Programm is not on the board. I get also not an warning. I find it out, when the blinky blinks after download again. this effect is very dangerous.

Is it possible to get an ready working example "uart pheriperal ble"? So can compile and debug. Why is this so compilcated ????

If someone to spend me real Support, i am very happy and i pay for this.

I Need it very fast.

Many thanks

RE: MIDI BLE Example NRF52DK

Stian Røed Hafskjold — Mon, 21 Nov 2016 09:03:02 GMT

Maybe you can use some code from this repo: github.com/.../blidino

RE: MIDI BLE Example NRF52DK

Roger Clark — Thu, 17 Nov 2016 23:13:15 GMT

You will need to carefully read the Midi BLE spec produced by Apple and implement their requirements in your code.

(See link in my answer)

RE: MIDI BLE Example NRF52DK

Remo — Thu, 17 Nov 2016 22:56:19 GMT

OK i found this UUID on example ble_app_uart and i changed it to one of the Apple's UUID. But not work,

#define NUS_BASE_UUID                  {{0x9E, 0xCA, 0xDC, 0x24, 0x0E, 0xE5, 0xA9, 0xE0, 0x93, 0xF3, 0xA3, 0xB5, 0x00, 0x00, 0x40, 0x6E}} /**< Used vendor specific UUID. */
#define NUS_BASE_UUID                  {{0x77, 0x72, 0xE5, 0xDB, 0x38, 0x68, 0x41, 0x12, 0xA1, 0xA9, 0xF2, 0x66, 0x9D, 0x10, 0x6B, 0xF3}} /**< MIDI I/O Characteristic */
#define NUS_BASE_UUID                  {{0x03, 0xB8, 0x0E, 0x5A, 0xED, 0xE8, 0x4B, 0x33, 0xA7, 0x51, 0x6C, 0xE3, 0x4E, 0xC4, 0xC7, 0x00}} /**< MIDI Service */

I think this Need more changes on the source.

RE: MIDI BLE Example NRF52DK

Stian Røed Hafskjold — Thu, 17 Nov 2016 11:53:02 GMT

I can confirm that we don't have any official examples for this.

RE: MIDI BLE Example NRF52DK

Roger Clark — Thu, 17 Nov 2016 01:06:52 GMT

AFIK. Nordic do not have a examples of Midi over BLE.

Bluetooth.org does not list a Midi service type www.bluetooth.com/.../services

If you want to use the Apple Midi service, youre probably going need to code it from their spec

developer.apple.com/.../Apple-Bluetooth-Low-Energy-MIDI-Specification.pdf

If you search this forum, you will find people have already investigated using the uart service but changing it to use Apple's 128 bit service ID for their proprietary Midi service / profile