Hello, what im trying to do is reverse engineering unknown device. What i need is catch a 16bytes data from it. Each clk's pulse speed is about 20 nanoseconds. I'm using stm32f4 discovery board, so i should be able to catch it as stm32 powerful uC. The fact that im really new in Keil, and i dont know if im doing it a propper way, for example to detect a GPIO goes down, im using this code
while (HAL_GPIO_ReadPin (GPIOC,GPIO_PIN_7) == 0){}
Is it proper way to do it? THe whole code with comments are:
while (1) { uint8_t collect_bits = 0; char string_array[21] = {0}; // HAL_Delay(200); while (HAL_GPIO_ReadPin (GPIOC,GPIO_PIN_9) == 0){} // wait until GPIOC 9 goes high while (HAL_GPIO_ReadPin (GPIOC,GPIO_PIN_9) == 1){} // wait until GPIOC 9 goes low for (int i = 0; i < 8; i++) // make a loop for reading byte { while (HAL_GPIO_ReadPin (GPIOC,GPIO_PIN_7) == 0){} // wait until clock goes high int32_t current_bit = HAL_GPIO_ReadPin (GPIOC,GPIO_PIN_9); // READ bit on PINC 9 collect_bits |= current_bit << i; // Shift current_bit to position i and // put it into collect_bits using bit wise OR while (HAL_GPIO_ReadPin (GPIOC,GPIO_PIN_7) == 1){} // wait until clock goes low, then repeat while loop untill we collect 8 bits } sprintf(string_array, "%X", collect_bits); // just simple convertation for PC output CDC_Transmit_FS((uint8_t*)string_array, sizeof(string_array)); // print result. // //break; /* USER CODE END WHILE */ /* USER CODE BEGIN 3 */ } /* USER CODE END 3 */ }
The problem is that output is not correct.What am i doing wrong? thanks
Surely a (simple) logic analyser or oscilloscope would be a more appropriate tool here?
This is probably not fast enough for you:
hobbycomponents.com/.../243-hobby-components-usb-8ch-24mhz-8-channel-logic-analyser
but that's the kind of idea ...
I have a very expensive oscilloscope, it can see nanosecond etc. I dont need to read data with oscilloscope or logic analazyer. Im making device that will read the data from that unknown stuff and print it on PC software. Btw what about 84mHz SPI? for 50 nanosecond clock, is it fast enough?