TMS320VC5501 datasheet(159/193 Pages) TI

159 / 193 page

Electrical Specifications

159

December 2002 − Revised November 2004

SPRS206H

5.10 External Interrupt and Interrupt Acknowledge (IACK) Timings

Table 5−19 and Table 5−20 assume testing over recommended operating conditions (see Figure 5−23 and

Figure 5−24).

Table 5−19. External Interrupt and Interrupt Acknowledge Timing Requirements

NO.

MIN

MAX

UNIT

tw(INTL)A

Pulse width, interrupt low, CPU active

3P†

tw(INTH)A

Pulse width, interrupt high, CPU active

1P†

† P = 1/CPU clock frequency in ns. For example, when running parts at 300 MHz, use P = 3.33 ns.

Table 5−20. External Interrupt and Interrupt Acknowledge Switching Characteristics

NO.

PARAMETER

MIN

MAX

UNIT

td(COH-IACKV)

Delay time, CLKOUT high to IACK valid‡

‡ In this case, CLKOUT refers to the CPU clock. Since CLKOUT cannot be programmed to reflect the CPU clock, there might be an extra delay

of a certain number of CPU clocks based on the ratio between the system clock shown on CLKOUT and the CPU clock. For example, if SYSCLK2

is shown on CLKOUT and SYSCLK2 is programmed to be half the CPU clock, there might be an extra delay of one CPU clock period between

the transition of CLKOUT and the specified timing. If system clock is programmed to be one-fourth of the CPU clock, there might be an extra delay

of 1, 2, or 3 CPU clocks between the transition of CLKOUT and the specified timing. The extra delay must be taken into account when considering

the MAX value for the timing under question. Note that if the CPU clock and the system clock shown on CLKOUT are operating at the same

frequency, there will be no extra delay in the specified timing.

INTx, NMI

Figure 5−23. External Interrupt Timings

CLKOUT

IACK

NOTE: The figure shows the case in which CLKOUT is programmed to show a system clock that is operating at the same frequency as

the CPU clock.

Figure 5−24. External Interrupt Acknowledge Timings

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