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Remove unneeded comments.

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This commit is contained in:
László Monda
2017-08-10 19:09:57 +02:00
parent 58f17ba344
commit 04e3532961
1 changed files with 16 additions and 63 deletions
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79
right/src/buspal/microseconds/microseconds_pit.c
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@@ -1,43 +1,15 @@
/*
* @file microseconds.c
* @brief Microseconds timer driver source file
*
* Notes: The driver configure PIT as lifetime timer
*/
#include "microseconds/microseconds.h"
#include <stdarg.h>
#include "bus_pal_hardware.h"
////////////////////////////////////////////////////////////////////////////////
// Definitions
////////////////////////////////////////////////////////////////////////////////
// Below MACROs are defined in order to keep this driver compabtile among all targets.
#if defined(PIT0)
#define PIT PIT0
#endif
#if defined(SIM_SCGC6_PIT0_MASK)
#define SIM_SCGC6_PIT_MASK SIM_SCGC6_PIT0_MASK
#endif
enum
{
enum {
kFrequency_1MHz = 1000000UL
};
////////////////////////////////////////////////////////////////////////////////
// Variables
////////////////////////////////////////////////////////////////////////////////
uint32_t s_tickPerMicrosecondMul8; //!< This value equal to 8 times ticks per microseconds
uint32_t s_tickPerMicrosecondMul8; // This value equals to 8 times ticks per microseconds
////////////////////////////////////////////////////////////////////////////////
// Code
////////////////////////////////////////////////////////////////////////////////
//! @brief Initialize timer facilities.
//!
//! It is initialize the timer to lifetime timer by chained channel 0
//! and channel 1 together, and set b0th channels to maximum counting period
// Initialize the timer to lifetime timer by chained channel 0 and
// channel 1 together, and set both channels to maximum counting period.
void microseconds_init(void)
{
uint32_t busClock;
@@ -60,84 +32,65 @@ void microseconds_init(void)
PIT->CHANNEL[0].TFLG = 1; // clear the timer 0 flag
PIT->CHANNEL[0].TCTRL = PIT_TCTRL_TEN_MASK; // start timer 0
/* Calculate this value early
* The reason why use this solution is that lowest clock frequency supported by L0PB and L4KS
* is 0.25MHz, this solution will make sure ticks per microscond is greater than 0.
*/
// Calculate this value early
// The reason why use this solution is that lowest clock frequency supported by L0PB and L4KS
// is 0.25MHz, this solution will make sure ticks per microscond is greater than 0.
busClock = get_bus_clock();
s_tickPerMicrosecondMul8 = (busClock * 8) / kFrequency_1MHz;
// Make sure this value is greater than 0
if (!s_tickPerMicrosecondMul8)
{
if (!s_tickPerMicrosecondMul8) {
s_tickPerMicrosecondMul8 = 1;
}
}
//! @brief Shutdown the microsecond timer
void microseconds_shutdown(void)
{
// Turn off PIT: MDIS = 1, FRZ = 0
PIT->MCR |= PIT_MCR_MDIS_MASK;
PIT->MCR |= PIT_MCR_MDIS_MASK; // Turn off PIT: MDIS = 1, FRZ = 0
}
//! @brief Read back running tick count
uint64_t microseconds_get_ticks(void)
{
uint64_t valueH;
uint32_t valueL;
#if defined(FSL_FEATURE_PIT_HAS_LIFETIME_TIMER) && (FSL_FEATURE_PIT_HAS_LIFETIME_TIMER == 1)
valueH = PIT->LTMR64H;
valueL = PIT->LTMR64L;
#else
// Make sure that there are no rollover of valueL.
// Because the valueL always decreases, so, if the formal valueL is greater than
// current value, that means the valueH is updated during read valueL.
// In this case, we need to re-update valueH and valueL.
do
{
do {
valueH = PIT->CHANNEL[1].CVAL;
valueL = PIT->CHANNEL[0].CVAL;
} while (valueL < PIT->CHANNEL[0].CVAL);
#endif // FSL_FEATURE_PIT_HAS_LIFETIME_TIMER
// Invert to turn into an up counter
return ~((valueH << 32) | valueL);
}
//! @brief Returns the conversion of ticks to actual microseconds
//! This is used to seperate any calculations from getting a timer
// value for speed critical scenarios
// This is used to seperate any calculations from getting a timer
// value for speed critical scenarios
uint32_t microseconds_convert_to_microseconds(uint32_t ticks)
{
// return the total ticks divided by the number of Mhz the system clock is at to give microseconds
return (8 * ticks / s_tickPerMicrosecondMul8); //!< Assumes system clock will never be < 0.125 Mhz
return (8 * ticks / s_tickPerMicrosecondMul8); // Assumes system clock will never be < 0.125 Mhz
}
//! @brief Returns the conversion of microseconds to ticks
uint64_t microseconds_convert_to_ticks(uint32_t microseconds)
{
return ((uint64_t)microseconds * s_tickPerMicrosecondMul8 / 8);
}
//! @brief Delay specified time
//!
//! @param us Delay time in microseconds unit
void microseconds_delay(uint32_t us)
{
uint64_t currentTicks = microseconds_get_ticks();
//! The clock value in Mhz = ticks/microsecond
// The clock value in Mhz = ticks/microsecond
uint64_t ticksNeeded = ((uint64_t)us * s_tickPerMicrosecondMul8 / 8) + currentTicks;
while (microseconds_get_ticks() < ticksNeeded)
{
;
while (microseconds_get_ticks() < ticksNeeded) {
}
}
//! @brief Gets the clock value used for microseconds driver
// Get the clock value used for microseconds driver
uint32_t microseconds_get_clock(void)
{
return get_bus_clock();