wschang0
commented
5 years ago M2351 doesn’t support DWT cycle counter. The clock source of SysTick could be the same as CPU. Therefore, you could use SysTick timer for cycle count.
From: user01-weeve [mailto:notifications@github.com] Sent: Tuesday, March 19, 2019 11:31 PM To: OpenNuvoton/M2351BSP Cc: Subscribed Subject: [OpenNuvoton/M2351BSP] Measuring Execution Time of a Piece of Code (#5)
Hi, I am trying to figure out exact number of CPU cycles taken by a piece of code. In one of the doc, I checked in use guide, DWT counter is mentioned in a block diagram which can be used to do this. But it doesn't work. Below is the piece of code I tried: uint32_t clock_cycles_counter; volatile unsigned int DWT_CYCCNT = (uint32_t )0xE0001004; //address of the register volatile unsigned int DWT_CONTROL = (uint32_t )0xE0001000; //address of the register volatile unsigned int SCB_DEMCR = (uint32_t )0xE000EDFC; //address of the register // configure and start the clock cycles counter clock_cycles_counter = 0; SCB_DEMCR = SCB_DEMCR | 0x01000000; DWT_CYCCNT = 0; DWT_CONTROL |= 1; ////// //////Code to be measured ///// // stop and get the counter value DWT_CONTROL &= ~1; clock_cycles_counter = DWT_CYCCNT;
// print the counter value printf("counter %d\n\r", clock_cycles_counter);
Always get '0'. Is the peripheral address mapped in above program correct? Has anyone tried another way to measure the time? Thank in advance
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Hi, I am trying to figure out exact number of CPU cycles taken by a piece of code. In one of the doc, I checked in use guide, DWT counter is mentioned in a block diagram which can be used to do this. But it doesn't work. Below is the piece of code I tried: uint32_t clock_cycles_counter; volatile unsigned int DWT_CYCCNT = (uint32_t )0xE0001004; //address of the register volatile unsigned int DWT_CONTROL = (uint32_t )0xE0001000; //address of the register volatile unsigned int SCB_DEMCR = (uint32_t )0xE000EDFC; //address of the register // configure and start the clock cycles counter clock_cycles_counter = 0; SCB_DEMCR = SCB_DEMCR | 0x01000000; DWT_CYCCNT = 0; DWT_CONTROL |= 1; ////// //////Code to be measured ///// // stop and get the counter value DWT_CONTROL &= ~1; clock_cycles_counter = DWT_CYCCNT;
// print the counter value printf("counter %d\n\r", clock_cycles_counter);
Always get '0'. Is the peripheral address mapped in above program correct? Has anyone tried another way to measure the time? Thank in advance