Toit
#sending numerical values via notification
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AbedN 02/22/2025 02:41 PM
Hi,
I'm trying to get my c enevlope to send a float value as a notification (it doesn't expect a response) to a toit container.
tried segmenting the float value into a uint_8 array then sending that via toit_msg_notify however i keep getting a "Guru Meditation" error, plus i don't think it's viable to do it this way afterall, so wondering if there's a better way.
Abdalrahim
I'm trying to get my c enevlope to send a float value as a notification (it doesn't expect a response) to a toit container.
tried segmenting the float value into a uint_8 array then sending that via toit_msg_notify however i keep getting a "Guru Meditation" error, plus i don't think it's viable to do it this way afterall, so wondering if there's a better way.
Abdalrahim
OPAbedNHi, I'm trying to get my c enevlope to send a float value as a notification (it doesn't expect a response) to a toit container. tried segmenting the float value into a uint_8 arra...
floitsch 02/23/2025 12:25 PM
Is the communication working otherwise? Is this specific to the float value?
Can you send a test buffer from the C side to the Toit side?
If yes, then you should just encode your float into a byte array and send it to the Toit side. There, you can then use
Can you send a test buffer from the C side to the Toit side?
If yes, then you should just encode your float into a byte array and send it to the Toit side. There, you can then use
io.LITTLE-ENDIAN
floitschIs the communication working otherwise? Is this specific to the float value? Can you send a test buffer from the C side to the Toit side? If yes, then you should just encode your f...
AbedN 02/25/2025 03:30 PM
here's my test buffer: extern "C" {
static toit_err_t on_created(void* user_data, toit_msg_context_t* context) {
echo_service_t* echo_service = static_cast<echo_service_t*>(user_data);
echo_service->msg_context = context;
uint8_t temp[4];
int length = 4;
for(int i = 0; i < 4; i++){
temp[i] = (uint8_t) 'x' + i;
}
if (toit_msg_notify(context, 3, temp, length, true) != TOIT_OK) {
std::printf("unable to send\n");
}
return TOIT_OK;
}
static toit_err_t on_created(void* user_data, toit_msg_context_t* context) {
echo_service_t* echo_service = static_cast<echo_service_t*>(user_data);
echo_service->msg_context = context;
uint8_t temp[4];
int length = 4;
for(int i = 0; i < 4; i++){
temp[i] = (uint8_t) 'x' + i;
}
if (toit_msg_notify(context, 3, temp, length, true) != TOIT_OK) {
std::printf("unable to send\n");
}
return TOIT_OK;
}
AbedN 02/25/2025 03:31 PM
and this is the error i'm getting: ELF file SHA256: c9ba8f10c5206ec7
Rebooting...
ESP-ROM:esp32c6-20220919
Build:Sep 19 2022
rst:0xc (SW_CPU),boot:0xc (SPI_FAST_FLASH_BOOT)
Saved PC:0x4001975a
SPIWP:0xee
mode:DIO, clock div:2
load:0x40875720,len:0x9c
load:0x4086c110,len:0xb6c
load:0x4086e610,len:0x23b8
entry 0x4086c110
[toit] INFO: starting <v2.0.0-alpha.174>
[toit] INFO: running on ESP32C6 - revision 0.1
unable to send
Guru Meditation Error: Core 0 panic'ed (Store access fault). Exception was unhandled.
Core 0 register dump:
MEPC : 0x40806b22 RA : 0x40807016 SP : 0x40830e90 GP : 0x40822da4
Rebooting...
ESP-ROM:esp32c6-20220919
Build:Sep 19 2022
rst:0xc (SW_CPU),boot:0xc (SPI_FAST_FLASH_BOOT)
Saved PC:0x4001975a
SPIWP:0xee
mode:DIO, clock div:2
load:0x40875720,len:0x9c
load:0x4086c110,len:0xb6c
load:0x4086e610,len:0x23b8
entry 0x4086c110
[toit] INFO: starting <v2.0.0-alpha.174>
[toit] INFO: running on ESP32C6 - revision 0.1
unable to send
Guru Meditation Error: Core 0 panic'ed (Store access fault). Exception was unhandled.
Core 0 register dump:
MEPC : 0x40806b22 RA : 0x40807016 SP : 0x40830e90 GP : 0x40822da4
floitsch 02/25/2025 03:37 PM
1
Try to use triple-backticks (`) for the code. That should make it easier to read.
1floitsch 02/25/2025 03:43 PMProgram your microcontrollers in a fast and robust high-level language. - toitlang/toit 
I think there are three things here:
1. we need to figure out what the return code of
2. you are passing in a buffer that is allocated on the stack (
3. the last parameter of the
1. we need to figure out what the return code of
toit_msg_notifyTOIT_ERR_NO_SUCH_RECEIVER2. you are passing in a buffer that is allocated on the stack (
uint8_t temp[4]return TOIT_OKmalloctoit_malloctoit_msg_notify3. the last parameter of the
toit_msg_notifyfree_on_failurefloitsch 02/25/2025 03:45 PM
I don't see any container starting at the beginning. So either they didn't have time yet, or it's not correctly configured. Either way, that's probably the reason the sending is failing: the other side is not (yet) there.
8 messages in total