Mercurial > ~darius > hgwebdir.cgi > stm32temp
comparison main.c @ 35:1fdfbad9eca7
Add 'cyc' command to test CM3 debug cycle counter.
author | Daniel O'Connor <darius@dons.net.au> |
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date | Mon, 11 Mar 2013 19:52:03 +1030 |
parents | 03592ca4d37e |
children | a38003b97de6 |
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34:07589f738e5e | 35:1fdfbad9eca7 |
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347 maxerr = err; | 347 maxerr = err; |
348 } | 348 } |
349 printf("Max err = %.3f\r\n", maxerr); | 349 printf("Max err = %.3f\r\n", maxerr); |
350 } else if (!strcmp("assert", argv[0])) { | 350 } else if (!strcmp("assert", argv[0])) { |
351 assert(0 == 1); | 351 assert(0 == 1); |
352 } else if (!strcmp("cyc", argv[0])) { | |
353 // From http://forums.arm.com/index.php?/topic/13949-cycle-count-in-cortex-m3/ | |
354 // via http://stackoverflow.com/questions/11530593/cycle-counter-on-arm-cortex-m4-or-m3/11530829#11530829 | |
355 uint32_t c1, c2, c; | |
356 volatile uint32_t *DWT_CYCCNT = (uint32_t *)0xe0001004; | |
357 volatile uint32_t *DWT_CONTROL = (uint32_t *)0xe0001000; | |
358 volatile uint32_t *SCB_DEMCR = (uint32_t *)0xe000edfc; | |
359 | |
360 *SCB_DEMCR = *SCB_DEMCR | 0x01000000; | |
361 *DWT_CONTROL = *DWT_CONTROL | 1 ; // enable the counter | |
362 c1 = *DWT_CYCCNT; | |
363 for (volatile int i = 0; i < 1000; i++) | |
364 ; | |
365 c2 = *DWT_CYCCNT; | |
366 if (c2 > c1) | |
367 c = c2 - c1; | |
368 else { | |
369 c = (0xffffffff - c1) + c2; | |
370 } | |
371 printf("Took %ld cycles\r\n", c); | |
352 } else if (!strcmp("zz", argv[0])) { | 372 } else if (!strcmp("zz", argv[0])) { |
353 NVIC_SystemReset(); | 373 NVIC_SystemReset(); |
354 } else { | 374 } else { |
355 printf("Unknown command\r\n"); | 375 printf("Unknown command\r\n"); |
356 } | 376 } |