System Time R5

The uz_SystemTime can be used to read the total uptime of the UltraZohm and the number of executed ISR routines on the R5 processor. See uz/uz_SystemTime/uz_SystemTime.h for API.

• Counter with 64-bit at 100 MHz for the uptime of the system.

• Uses Xilinx AXI Timer v2.0

• 64 Bit Mode enabled

• Timer will overflow in >5000 years after system boot

• Works with two 32-bit counter (lower and upper bits)

• Only one instance of system time is possible and only on the R5

Usage

• Include uz/uz_SystemTime/uz_SystemTime.h and call the API

• Intended for usage in the ISR of the R5 processor

• Initialize the function outside of the ISR by calling uz_SystemTime_init()

• Call uz_SystemTime_ISR_Tic() to start a time measurement, e.g., the first line of ISR

• Call uz_SystemTime_ISR_Toc() to stop the time measurement, e.g., last line of ISR

• Call the getter functions to read the system time that was read by the last tic call

• A lock prevents the call to toc before tic was called

• Calling toc before tic fires an assertion

• Calling any function of the component before uz_SystemTime_init() fires an assertion

Warning

The getter functions, e.g., uz_SystemTime_GetUptimeInMs(), return the system time that was read out at the last call to uz_SystemTime_ISR_Tic()! This is intended behavior to have the system time aligned with the start of the ISR.

Example

The variable uptimeInMs holds the uptime in milliseconds at the start of ISR_Control. The variable IsrExectionTimeInUs holds the execution time of the ISR, which will be about 100 microseconds + some time for reading the timer.

void ISR_Control(void *data)
{
  uz_SystemTime_ISR_Tic();
  float uptimeInMs=uz_SystemTime_GetUptimeInMs();
  usleep(100); // Do nothing for 100 microseconds
  uz_SystemTime_ISR_Toc();
}

int main (void){
float IsrExectionTimeInUs=uz_SystemTime_GetIsrExectionTimeInUs();
}

IP Core

• The AXI Timer v2.0 IP core is abstracted by uz_AxiTimer64Bit.h which wraps the Xilinx drivers (xtmrctr.h)

• Timer is called timer_uptime_64bit in Vivado Block Design

Fig. 305 timer_uptime_64bit IP core for system time