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PEB 20550 PEF 20550 Application Hints 5.8 Supervision Functions 5.8.1 Hardware Timer Hardware Timer The ELIC provides a programmable hardware timer which can be used for three purposes: – General purpose timer for continuously interrupting the µP at programmable time intervals. – Timer to define the last look period for signaling channels at the CFI (see chapter 5.5.1). – Timer to define the FSC multiframe generation at the CFI (CMD2:FC2 … 0 = 111, see chapter 5.2.2.3). Normally in a system only one of these functions is required and therefore active at a time. However, it is also possible to have any combination of these functions active, if it is acceptable that all three applications use the same timer value. The timer period can be selected from 250 µs up to 32 ms in increments of 250 µs. T T Timer Start CMDR : ST = 1 (CMDR : TIG = 1) (ISTA : TIN) LL Sampling Multifr. Sync. (ISTA : TIN) LL Sampling Multifr. Sync. T = (TVAL6...0 + 1) x 250 µs LL : Last Look Timer Stop TIMR = XX ITD08093 Figure 113 Timer Applications Semiconductor Group 331 01.96
