Description
Application-defined function to get current CPU timestamp timer count.
Files
cpu_core.h / Application’s cpu_bsp.c
Prototype
Arguments
None.
Returned Value
CPU timestamp timer count value.
Required Configuration
CPU_TS_TmrRd() is an application/BSP function that must be defined by the developer if either of the following CPU features is enabled in cpu_cfg.h :
- CPU timestamps when either
CPU_CFG_TS_32_ENorCPU_CFG_TS_64_ENisDEF_ENABLED(see section 6-1) - CPU interrupts disabled time measurements when
CPU_CFG_INT_DIS_MEAS_ENis#define'd(see section 7-1)
Notes / Warnings
CPU timestamp timer count values must be returned via word-size-configurable CPU_TS_TMR data type. If timer has more bits, truncate timer values’ higher-order bits greater than the configured CPU_TS_TMR timestamp timer data type word size. However, since the timer must not have less bits than the configured CPU_TS_TMR timestamp timer data type word size; CPU_CFG_TS_TMR_SIZE must be configured so that all bits in CPU_TS_TMR data type are significant. In other words, if timer size is not a binary-multiple of 8-bit octets (e.g. 20-bits or even 24-bits), then the next lower, binary-multiple octet word size should be configured (e.g. to 16-bits). However, the minimum supported word size for CPU timestamp timers is 8-bits.
CPU timestamp timer should be an ‘up’ counter whose values increase with each time count. If timer is a ‘down’ counter whose values decrease with each time count, then the returned timer value must be ones-complemented.
When applicable, CPU timestamp timer period should be less than the typical measured time but must be less than the maximum measured time; otherwise, timer resolution inadequate to measure desired times.