Hello All,

I am using Quectel's BG96 module to send data to some cloud services using MQTT Protocol.
'Quectel_BG96_MQTT_Application_Note_V1.0' is documented well and I am following the same.
According to its section 3.2.8, we need to send CTRL+Z, to send user data to cloud, once ">" is responded from the module.

While using QNavigator (Quectel's AT Command tester) I follow the same procedure and I can publish my data to the cloud service.

The problem is that I don't know how to send CTRL+Z via UART, specifically in this case.
Can any one help me out here?

Suppose I want to publish "Quectel" on a cloud, how should I embed CTRL+Z with the string "Quectel" in my UART Transmission code?

Thanks & Regards,
Maunik Patel

 

I believe it is DEC 26 or 1A hex.
Max.

 

Hello All,

I am using Quectel's BG96 module to send data to some cloud services using MQTT Protocol.
'Quectel_BG96_MQTT_Application_Note_V1.0' is documented well and I am following the same.
According to its section 3.2.8, we need to send CTRL+Z, to send user data to cloud, once ">" is responded from the module.

While using QNavigator (Quectel's AT Command tester) I follow the same procedure and I can publish my data to the cloud service.

The problem is that I don't know how to send CTRL+Z via UART, specifically in this case.
Can any one help me out here?

Suppose I want to publish "Quectel" on a cloud, how should I embed CTRL+Z with the string "Quectel" in my UART Transmission code?

Thanks & Regards,
Maunik Patel

The "control codes" are the first 32 ASCII codes, so they are the lower 5 bits of the 7-bit ASCII sequence.

Since they couldn't be typed directly from a terminal keyboard and it was sometimes desired to do so, a key was added to the keyboard that suppressed the upper two bits. Not surprisingly, this was called the "control" key.

Since Z has an ASCII value of 0x5A (01011010), suppressing the upper two bits yields (00011010) or 0x1A. In decimal, this is 26.

 

@maunik12 1Ah Also know as the Substitution Character.
Max.

 

Hello @MaxHeadRoom and @WBahn,

Thank you for your valuable time.

uint8_t ctrl_z = 0x1A; //'0x1A', 26, '26';

char msg[] = {'0x41','0x42','0x43','0x1A'};
char msg[] = {'65', '66', '67','26'};

HAL_UART_Transmit_IT(&huart1,(uint8_t *)msg, sizeof(msg));
HAL_UART_Transmit_IT(&huart1, &ctrl_z, sizeof(ctrl_z));

 

Hello @MaxHeadRoom and @WBahn,

Thank you for your valuable time.
Description given by WBahn is something, which I have never found on internet. Very well @WBahn

Please ignore my previous reply. It was sent by mistake.

Yes, I know that CTRL+Z = 26(DEC), 0x1A(Hex), but I don't know exactly how to send it.
Look at a copy of my code below.

uint8_t ctrl_z = 26; // '26', 0x1A, '0x1A' (I have tried these 3 options also)
char msg[] = "Quectel";

HAL_UART_Transmit_IT(&huart1,(uint8_t *)msg, sizeof(msg));
HAL_UART_Transmit_IT(&huart1, &ctrl_z, sizeof(ctrl_z));​

Here, I tried sending CTRL+Z in above mentioned 4 ways.
Some how, I can't Publish my data.

The APIs used for transmission are for STM32L4 series controller.

Feel free if you need some more details from my side.

Thanks & Regards,
Maunik Patel

 

I only program in Assembly but all that should be needed is to transmit via the USART register by loading the hex value 0x1A.
Max.

 

Hello,

I have the same problem. Did you find a way?

Regards,
Nik

 

CTRL-Z is decimal 26.
Send 26 to the UART transmiiter.

 

try to connect a terminal emulator (show hex value on screen) on a separate pc to the uart output from your hardware.

Look at the output and check if hex 1A is received.
if not problem in your mechanism.
if received look at receiver part; how did you respond after the prompt to early or to late.
did you generate the correct headers?
what error code is generated by the cloud?
see: http://mqtt.org/new/wp-content/uploads/2009/06/MQTT-SN_spec_v1.2.pdf

Picbuster