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lp_timer test : add a minimum delta value

pull/5737/head
jeromecoutant 2017-12-20 14:35:00 +01:00
parent 9ebefcd63d
commit 9a43912177
1 changed files with 5 additions and 1 deletions
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6
TESTS/mbed_drivers/lp_timer/main.cpp
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@ -51,13 +51,17 @@ extern uint32_t SystemCoreClock;
* For K64F DELTA = (80000 / 120000000) * 1000000 = 666[us]
* For NUCLEO_F070RB DELTA = (80000 / 48000000) * 1000000 = 1666[us]
* For NRF51_DK DELTA = (80000 / 16000000) * 1000000 = 5000[us]
*
* As low power timer cannot be too much accurate, this DELTA should not be more precise than 500us,
* which corresponds to a maximum CPU clock around 130MHz
*/
#define US_PER_SEC 1000000
#define US_PER_MSEC 1000
#define TOLERANCE_FACTOR 80000.0f
#define US_FACTOR 1000000.0f
#define CLOCK_MAX 130000000
static const int delta_sys_clk_us = ((int) (TOLERANCE_FACTOR / (float) SystemCoreClock * US_FACTOR));
static const int delta_sys_clk_us = (SystemCoreClock < CLOCK_MAX? ((int) (TOLERANCE_FACTOR / (float) SystemCoreClock * US_FACTOR)):((int) (TOLERANCE_FACTOR / (float) CLOCK_MAX * US_FACTOR)));
/* When test performs time measurement using Timer in sequence, then measurement error accumulates
* in the successive attempts. */