21.5.2 Single Period Mode

When the PIT64B_MR.CONT bit is written to 0, the PIT64B produces a single timer event. The timer period starts as soon as the START bit, in the Control register (PIT64B_CR), is written to 1. The period is defined by configuring the LSBPERIOD field in the LSB Period register (PIT64B_LSBPR) and the MSBPERIOD field in the MSB Period register (PIT64B_MSBPR). When the START command is issued, the 64-bit timer loads 0 and increments up to LSBPERIOD and MSBPERIOD field value minus 1, then automatically reloads 0 and stops.

When time reaches the maximum value, the PERIOD flag, in the Interrupt Status register (PIT64B_ISR), is set. No other period will be started until a new START command is issued.

After a period is started and while it is not elapsed, any new values written in PIT64B_MR, PIT64B_LSBPR or PIT64B_MSBPR have no effect on the current period if bit PIT64B_MR.SMOD=0 (see Figure 21-2)

If PIT64B_MR.SMOD=1 a start is also performed as soon as PIT64B_LSBPR is written, thus a modification of the period can be performed on-the-fly with a single write operation if the period requires no more than 32 bits. When writing a 64-bit value, the 32-bit MSB part must be configured first, followed by the 32-bit LSB part (see Figure 21-3). When configuring a value lower or equal to 32 bits after processing a period defined on 64 bits, first PIT64B_MSBPR must be written to 0, and then the 32-bit LSB must be written into PIT64B_LSBPR.

If PIT64B_CR.SWRST is written to 1, the current period is immediately stopped.