GET/POST with pausing time

mavishak commented 3 years ago

16/05/2021

Sometimes communication gets stuck in the context of GET and / or POST requests.

Explanation:

'GET', this is request asking the database whether the system is turned ON or OFF (i.e. does or does not receive alerts, respectively). This request is triggred periodicaly by the system to check whether the configurations required by the user has changed. There is a paussing time count performed by TIMER2.

'POST' this when the system detects traffic, and spontaneously sends a message to the database. After sending such a message, there is a period of time in which we are not interested in further traffic manifestations. This time period is also counted by timer, this time TIMER3.

TIMER4 - Its role is to schedule in communication with the ESP. If it takes too long for a response from the ESP, the timer expires and a proper response must be decided.

Our suspicion falls on the multiplicity and length of interrpts and events.

Debugging process:

see the pdf notes the process - Debugging POST-GET with pausing time.pdf

We came to the conclution that the time each event demands relative to the amount of times we want each event to accur is not porpotional. And that the comunication between the ESP and Firebase is being interrupted to often. We saw clearly that when allowing all the timers interuptions the comunication was much slower.

We have two proposles:

compine all timer interrupts to one interrupt that will set up to 3 counters. The timer will be enabled at the beginning of the program and from then on an interrupt will accure once a second. Reasoning - this way during comunication there won't be three intrupts disturbing it but one.
Try and implement an ESP server - send the request to switch the alerts on or off directly to it. That whay we will not need to send a GET request to Firebase and free the microcontroller form a large anount of events.

mavishak commented 3 years ago

ESP8266 as a server:

From what we understoof inorder to configure the ESP as server we needed to configure it as an access point (AP).

AT+CWMODE=2 // configure as AP AT+CWSAP=, // from what we saw we could only set the password when using the given ssid (AT+CWSAP?)

After processing thes two AT commands we could access the AP from out computer/smartphone

AT+CWLIF // prints out all the current IP's that are connected to the ESP access point.

We didn't quite understand if this could actually help us, but we will look further in to the subject. A helpful link - ESP8266 AP & STA MODE TOGETHER

Note: for this test we connected the esp directly to the Tx and Rx of the PC

NaomiCreate commented 3 years ago

Our instructor recommended that we reduce the number of prints to Tera Term ,so that we can dubug the software more efficiently. Therefore we changed the implementation of uart2 so that printing to Tera Term will occur after each line only.

We continued with a debugging session that included tests for the timers, and the motion sensor. Attached is the documentation file of the debugging session:

Debug session 23.5.21-24.5.pdf

The bug we found was: We cleaned the sensor interrupt bit only when timer 3 came to a timeout, instead of clearing that bit at the beginning of the interrupt. With bug:

void EXTI4_IRQHandler(void) 
{   
       if(timeout_done_timer3())    
       {        
                EXTI->PR |= 0x00000010;     
        add_event(alert_Handler);       
                set_timeout_timer3(10);     
        }
}

The fix:

void EXTI4_IRQHandler(void) 
{   
       EXTI->PR |= 0x00000010;  
       if(timeout_done_timer3())    
       {            
        add_event(alert_Handler);       
                set_timeout_timer3(10);     
        }
}

mavishak / cnss-embedded