vMMAC_SetChannel() throwing WATCHDOG exception

[mguc]

Hello

I'm using a JN5168 module running Contiki and I've currently an issue where I change the channel quite frequently and sometimes it gets stuck when calling vMMAC_SetChannel() and it throws a WATCHDOG exception and reboots. Can anyone help me with this problem? The watchdog timer value is set to its maximum value of 16392ms. I'm using the latest SDK "JN-SW-4163, Build 1416".

Log output (for futher details check https://github.com/contiki-os/contiki):

WATCHDOG EXCEPTION @ $0008967e EA: 0200147c SK: 04007f30 HP: 04007728
REGS: R00-03: 00 04007f30 000001b6 04007f34
R04-07: 00 00000006 0000000e 0000000a
R08-0b: 20 00089674 0000000c 040000ac
R0c-0f: b0 7bafdf6f d7ffff5e feaf7ffc

Part of the map file:

.text.vMMAC_IntHandlerBbc
0x0000000000089606 0x1a /JN-SW-4163/Components/Library/libMMAC_JN516x.a(MMAC.o)
0x0000000000089606 vMMAC_IntHandlerBbc
.text.vMMAC_Enable
0x0000000000089620 0x24 /JN-SW-4163/Components/Library/libMMAC_JN516x.a(MMAC.o)
0x0000000000089620 vMMAC_Enable
.text.vMMAC_EnableInterrupts
0x0000000000089644 0x23 /JN-SW-4163/Components/Library/libMMAC_JN516x.a(MMAC.o)
0x0000000000089644 vMMAC_EnableInterrupts
.text.vMMAC_SetChannel
0x0000000000089667 0x46 /JN-SW-4163/Components/Library/libMMAC_JN516x.a(MMAC.o)
0x0000000000089667 vMMAC_SetChannel
.text.vMMAC_SetChannelAndPower
0x00000000000896ad 0x93 /JN-SW-4163/Components/Library/libMMAC_JN516x.a(MMAC.o)
0x00000000000896ad vMMAC_SetChannelAndPower

With kind regards

Marko

[mguc]

Hello everyone

I was able to solve the problem with a workaround by using bJPT_RadioSetChannel() instead of vMMAC_SetChannel(). The Contiki radio driver for the JN516x is using the MMAC and JPT API to control the radio settings and that might be a problem (this should be confirmed or denied by NXP). For now I'm happy with the solution, but it still doesn't fix the real problem. Here is the disassembly of both functions, maybe someone of the NXP developers can take a look.

Disassembly of section .text.vMMAC_SetChannel:

00000000 <vMMAC_SetChannel>:
0: 47 a4 40          b.entri 0x2,0x2
3: 05 43               b.mov r10,r3
5: 30 61 20          b.addi r3,r1,0x4
8: 00 80               b.movi r4,0x0
a: 48 00 00          b.jal a <vMMAC_SetChannel+0xa>
d: cc f0 43 69      b.lwz r7,-0x6940(r16)
11: 00 c0             b.movi r6,0x0
13: cc d0 03 69   b.sw -0x6940(r16),r6
17: cc b0 7e 29   b.lwz r5,-0x6b84(r16)
1b: 34 a5 f0         b.andi r5,r5,0xf
1e: cc d0 60 79   b.lwz r6,-0x61fc(r16)
22: 34 c6 f0         b.andi r6,r6,0xf
25: 60 c6 29        b.or r6,r6,r5
28: 41 06 f7         b.bnei r6,0x0,17 <vMMAC_SetChannel+0x17>
2b: cd 50 10 79   b.sw -0x61f8(r16),r10
2f: cc d0 51 29    b.lwz r6,-0x6b78(r16)
33: 34 c6 a0       b.andi r6,r6,0x5
36: 41 06 e0       b.bnei r6,0x0,3d <vMMAC_SetChannel+0x3d>
39: cc f0 03 69    b.sw -0x6940(r16),r7
3d: 30 61 20       b.addi r3,r1,0x4
40: 48 00 00       b.jal 40 <vMMAC_SetChannel+0x40>
43: 47 b4 40       b.reti 0x2,0x2

Disassembly of section .text.bJPT_RadioSetChannel:

00000000 <bJPT_RadioSetChannel>:
0: 3c e3 50                      b.sfleui r3,0xa
3: 47 27 00                      b.bf 11 <bJPT_RadioSetChannel+0x11>
6: 38 e0 58                      b.ori r7,r0,0x1a
9: 3d 23 d8                      b.sfltui r3,0x1b
c: 64 63 3a                      b.cmov r3,r3,r7
f: 0e 80                            b.j 14 <bJPT_RadioSetChannel+0x14>
11: 38 60 d0                    b.ori r3,r0,0xb
14: 8c 60 10 78 00 40     b.sw 0x2001e08(r0),r3
1a: 0c 00                         b.j 1a <bJPT_RadioSetChannel+0x1a>

[mguc]

Hello again

This issue is still open and it would be nice if one of the NXP moderators could make a statement or at least try to help me. Is there a scenario where it could get stuck in this function? E.g. if certain interrupts or peripherals are enabled? I tried to replace it with vMMAC_SetChannelAndPower() and it still happens. After removing the function call in my code the watchdog exception disappeared. Thank you for your help!

With kind regards

Marko