Zephyr crashing when I connect to a device

[DiBosco]

 Vidar Berg has been helping me connect to a device and I am finally able to do that, but as soon as I do, Zephyr crashes.

This is with a lightly modified central_uart project

[00:00:00.024,810] <0x1b>[0m<inf> central_uart: Scan module initialized<0x1b>[0m␍␊

[00:00:00.024,810] <0x1b>[0m<inf> central_uart: NUS Client module initialized<0x1b>[0m␍␊

[00:00:00.029,846] <0x1b>[0m<inf> central_uart: Scanning successfully started<0x1b>[0m␍␊

[00:00:00.093,719] <0x1b>[0m<inf> central_uart: Filters matched. Address: E8:A0:DB:24:21:62 (random) connectable: 1<0x1b>[0m␍␊

[00:00:00.289,886] <0x1b>[0m<inf> central_uart: Connected: E8:A0:DB:24:21:62 (random)<0x1b>[0m␍␊

[00:00:00.290,039] <0x1b>[1;33m<wrn> central_uart: Failed to set security: -12<0x1b>[0m␍␊

[00:00:00.290,100] <0x1b>[1;31m<err> central_uart: Stop LE scan failed (err 0)<0x1b>[0m␍␊

[00:00:00.441,497] <0x1b>[0m<inf> central_uart: MTU exchange done<0x1b>[0m␍␊

ASSERTION FAIL [conn] @ WEST_TOPDIR/zephyr/subsys/bluetooth/host/gatt.c:5433␍␊

⇥ invalid parameters␍␊

␍␊

[00:00:01.791,351] <0x1b>[0m<inf> central_uart: Service discovery completed<0x1b>[0m␍␊

[00:00:01.800,994] <0x1b>[1;31m<err> os: r0/a1: 0x00000004 r1/a2: 0x00001539 r2/a3: 0x20000b60<0x1b>[0m␍␊

[00:00:01.800,994] <0x1b>[1;31m<err> os: r3/a4: 0x00000004 r12/ip: 0x00000000 r14/lr: 0x000217df<0x1b>[0m␍␊

[00:00:01.801,025] <0x1b>[1;31m<err> os: xpsr: 0x21000000<0x1b>[0m␍␊

[00:00:01.801,025] <0x1b>[1;31m<err> os: Faulting instruction address (r15/pc): 0x00031072<0x1b>[0m␍␊

[00:00:01.801,086] <0x1b>[1;31m<err> os: >>> ZEPHYR FATAL ERROR 4: Kernel panic on CPU 0<0x1b>[0m␍␊

[00:00:01.801,116] <0x1b>[1;31m<err> os: Current thread: 0x20002568 (BT RX WQ)<0x1b>[0m␍␊

[00:00:01.869,415] <0x1b>[1;31m<err> os: Halting system<0x1b>[0m␍␊

The program crashes here:

 

return snprintk(str, len, "%02X:%02X:%02X:%02X:%02X:%02X (%s)",

addr->a.val[5], addr->a.val[4], addr->a.val[3],

addr->a.val[2], addr->a.val[1], addr->a.val[0], type);

Which is in

addr.h (sic) Quite what code is doing in a header file is beyond me.

The prototype for the function is this:

int bt_addr_le_to_str(const bt_addr_le_t *addr, char *str, size_t len);

The values passed look reasonable to me.

addr->a.val[0]-[5] have the correct MAC address in it

str has (in decimal) 23 0 ... in it so that looks like it's just got a single character and anyway,

it shouldn't make a difference because, surely, that's being written into.

len = 30

type ends up with "random" in it.

I am assuming

snprintk is based on

snprint and so shouldn't copy more than len bytes anyway.

The string being used is that is passed into bt_addr_le_to_str is:

char addr[BT_ADDR_LE_STR_LEN];

and BT_ADDR_LE_STR_LEN is set to 30 so that all stacks up nicely.

Can anyone give me some pointers as to what might be wrong here?

BTW  Vidar Berg that little project you sent me does not crash like this, but I can't

see where you set up the characteristics for that project, there is no reference to

BT_GATT_SERVICE_DEFINE anywhere in it. I would happily just mod that if I could work out how you've set up

its service and characteristics.

Thanks

[DiBosco]

So are you saying the central_uart project needs to be modified (in this case  the one you supplied) so that the Rx characteristic in central subscribes to the Tx characteristic in the remote node?

When I use your peripheral_uart to talk to your central with my UUIDs in, I don't need to do anything else other than send data into the UART on the peripheral and it appears on the central_uart project's UART output.

If I look with nrf connect on my Android  phone, the Tx  on the remote node - whether it be the Nordic DK running peripheral_uart, or our custom device, (which is the RX on the central_uart project) it is notify only, so why would it work on peripheral_uart and not our custom device. What am I  not understanding here?

[Vidar Berg]

I thought you were using the Nordic UART service with custom UUIDs. However, after looking at the the nRF Connect screendump you shared again, I notice several differences. For instance, your service includes three or more characteristics, while the UART service only has two. The client code I provided will only subscribe to notifications from the first characteristic with UUID:651135b0-dfe9-45a2-95c1-46552a8a77e2.

I don't know which characteristics the peripheral is supposed to send notifications on in your case.

[DiBosco]

I've tried the 52840DK using your peripheral UART and that works. So I have done

UART         |                                BLE                                                               | UART

PC UART<->CENTRAL_UART on 52840<-><PERIPHERAL_UART on 528040<->PC UART

When I try to connect to the custom unit, which uses the very same UUIDs as your custom program, rather than peripheral_uart, it does not work.

The custom unit has successfully done exactly the same thing I'm trying to achieve here, but with a Raspberry Pi: 

UART         |                                BLE                                  | UART

PC UART <-> Raspberry Pi with BLE <-> Custom Unit<->STM32

I want to replace that with

UART         |                                BLE                                    | UART

PC UART <-> CENTRAL_UART on 52840<-> Custom Unit<->STM32

BTW, I know how crazy this is, but it's what we've been asked to do.

The custom unit's service for which you had the screen shot has the following setup in its firmware where Rx is data going into it and Tx is data going out.

// the service
#define BASE_UUID128   "2a1f963c-143a-4f7d-9107-6315196a02a6"
#define BASE_UUID16    0x963c
// BLE Data into the custom unit (so the central_uart I'm trying to get working will write into this)
#define RX_LENGTH      240
#define RX_UUID128     "651135b0-dfe9-45a2-95c1-46552a8a77e2"
#define RX_UUID16      0x35b0
// Not sued for UART comms
#define RX_ACK_LENGTH  2
#define RX_ACK_UUID128 "946ba79e-3162-46d5-9ba7-8a9d08c11ff0"
#define RX_ACK_UUID16  0xa79e
// Data out from the custom unit into the central_uart over Bluetooth
#define TX_LENGTH      240
#define TX_UUID128     "e7d6274e-b765-11e9-a2a3-2a2ae2dbcce4"
#define TX_UUID16      0x274e
// Unused for this UART function
#define TX_ACK_LENGTH  2
#define TX_ACK_UUID128 "e7d629ba-b765-11e9-a2a3-2a2ae2dbcce4"
#define TX_ACK_UUID16  0x29ba

The custom unit is running an older Nordic device and I have successfully talked to it the custom unit by writing a Qt program on Linux to talk directly to it. So, the point being we know the custom unit works with these UUIDs

I have tried swapping RX and TX round in custom_client.h just in case there was a BLE equivalent of a 2/3 swap needed, but that does not help.

i.e.

/** @brief UUID of the TX Characteristic. **/

#define BT_UUID_CUSTOM_SRV_RX_VAL \

BT_UUID_128_ENCODE(0x651135b0, 0xdfe9, 0x45a2, 0x95c1, 0x46552a8a77e2)

/** @brief UUID of the RX Characteristic. **/

#define BT_UUID_CUSTOM_SRV_TX_VAL \

BT_UUID_128_ENCODE(0xe7d6274e, 0xb765, 0x11e9, 0xa2a3, 0x2a2ae2dbcce4)

One ot her slight annoyance that needs sorting is this that is spat out of the UART at boot:

*** Booting nRF Connect SDK v2.8.0-a2386bfc8401 ***␍␊

*** Using Zephyr OS v3.7.99-0bc3393fb112 ***␍␊

If I search for "Booting nRF Connect" in VSC it does not give me any hits. Do you

know where that is in the source so I can get rid of it please?

[Vidar Berg]

I'm wondering if there any specific requirements for interfacing with your peripheral device or if it behaves just like the original NUS sample. For instance, if it requires notifications to be enabled on more than one characteristic to allow notifications to be sent or some kind of handshake, etc. Either way, I think it might be faster to use the nRF Connect app to determine what works and what doesn't. For example, you can check if you're able to receive data if you only enable notifications for the e7d6274e-b765-11e9-a2a3-2a2ae2dbcce4 characteristic:

DiBosco said:

One ot her slight annoyance that needs sorting is this that is spat out of the UART at boot:

You can disable the boot banners by adding the following 2 lines to your project configuration file:

CONFIG_NCS_BOOT_BANNER=n
CONFIG_BOOT_BANNER=n

[DiBosco]

Thanks  for the boot banner tip.

On the subject of writing from the Android app, I have made  some progress, This system is quite complex and the remote unit only writes when requested by a convoluted message, so I found what the standard debug request header is and wrote those 32 bytes using the BLE Scanner app by writing to characteristic UUID

0x651135b0, 0xdfe9, 0x45a2, 0x95c1, 0x46552a8a77e2

Now, unless and until I actually hit notify for the

0xe7d6274e, 0xb765, 0x11e9, 0xa2a3, 0x2a2ae2dbcce4

characteristic, I got nothing back. When I did hit notify then the
remote node wrote some valid data into the phone.

Is the issue that on this Zephyr app we're not subscribing
(is that the right word) to the read characteristic?

I'm assuming that should go on in the

bt_custom_handles_assign

function?