CPU_TS_TmrRd

Description

Application-defined function to get current CPU timestamp timer count.

Files

cpu_core.h / Application’s cpu_bsp.c

Prototype

          CPU_TS_TMR  CPU_TS_TmrRd (void);

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_EN or CPU_CFG_TS_64_EN is DEF_ENABLED. See Timestamps Configuration.
CPU interrupts disabled time measurements when CPU_CFG_INT_DIS_MEAS_EN is #define'd. See Interrupts Disabled Time Measurement Configuration.

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.

Implementation Template

Listing - CPU_TS_TmrRd() implementation template

          CPU_TS_TMR  CPU_TS_TmrRd (void)
          {
              CPU_TS_TMR  ts_tmr_cnts;
           
              ...
              ts_tmr_cnts =  /* Insert code to get/return CPU timestamp timer counts. */ ;
              ...
           
              return (ts_tmr_cnts);
          }

16-bit Up Timer Example

Listing - 16-bit Up timer example

          CPU_TS_TMR  CPU_TS_TmrRd (void)
          {
              CPU_TS_TMR  ts_tmr_cnts;  /* sizeof(CPU_TS_TMR) = 16 bits */
           
           
              ts_tmr_cnts =  /* Insert code to read 16-bit up timer value. */ ;
           
              return (ts_tmr_cnts);
          }

16-bit Down Timer Example

Listing - 16-bit Down timer example

          CPU_TS_TMR  CPU_TS_TmrRd (void)
          {
              CPU_INT16U  tmr_val;
              CPU_TS_TMR  ts_tmr_cnts;  /* sizeof(CPU_TS_TMR) = 16 bits */
           
           
              tmr_val     =             /* Insert code to read 16-bit down timer value. */ ;
              ts_tmr_cnts = ~tmr_val;   /* Ones-complement     16-bit down timer value. */
           
              return (ts_tmr_cnts);
          }

32-bit Up Timer Example

Listing - 32-bit Up timer example

          CPU_TS_TMR  CPU_TS_TmrRd (void)
          {
              CPU_TS_TMR  ts_tmr_cnts;  /* sizeof(CPU_TS_TMR) = 32 bits */
           
           
              ts_tmr_cnts =  /* Insert code to read 32-bit up timer value. */ ;
           
              return (ts_tmr_cnts);
          }

48-bit Down Timer Example

          CPU_TS_TMR  CPU_TS_TmrRd (void)
          {
              CPU_INT64U  tmr_val;
              CPU_TS_TMR  ts_tmr_cnts;  /* sizeof(CPU_TS_TMR) = 32 bits */
           
           
              tmr_val     =                       /* Insert code to read 48-bit down timer value.        */ ;
              ts_tmr_cnts = (CPU_TS_TMR)tmr_val;  /* Truncate 48-bit timer value to 32-bit timestamp ... */
                                                  /* ... timer data type.                                */
              ts_tmr_cnts = ~ts_tmr_cnts;         /* Ones-complement truncated  down timer value.        */
           
              return (ts_tmr_cnts);
          }