Timer input capture mode

hi, i am working with an example from the book Mastering STM32 written by Carmine Noviello.

The example is the 6th of chapter11, it is about Input capture mode.

I have a nucleo board STM32F401RE and i am building examples with STM32CUBEIDE tool.

I have configured two timers:

i use TIM1 in DMA circular mode to blink the LED PA5, which is high every 50khz.

i want detect this frequency by connecting the led to channel 1 of TIM3 in input capture mode.

TIM3 clock is connected to LSE through the MCO pin, which is running at 32768 hz.

I configured TIM3 in DMA circular mode so that when the LED is high, the content of CCR is trasferred to a 16bit Captures array of two elements(Captures[2]).

The DMA transfer is of halfword size since the CCR1 is a 16 bit register.

The global variable captureDone is set to 1 by the HAL_TIM_IC_CaptureCallback() callback function, which is invoked at the end of the capture process.

When this happens the frequency of the sample signal is computed using the following equation:

if (captureDone != 0) {

          if (captures[1] >= captures[0]) {

             diffCapture = (captures[1] - captures[0]);

          }else{

             diffCapture = (htim3.Instance->ARR - captures[0]) + captures[1];

          }

          frequency = LSE_VALUE/ (htim3.Instance->PSC + 1);

          frequency = (float) frequency / diffCapture;

          sprintf(msg, "Input frequency: %.3f\r\n", frequency);

          HAL_UART_Transmit(&huart2, (uint8_t*) msg, strlen(msg), HAL_MAX_DELAY);

          while (1);

        }

The problem is that is executed the ELSE statement even if from the debugging i read that captures[1] has a value greater than captures[0].

Can you help with this exercise please?