TMS320F2811PBKA datasheet(115/170 Pages) TI

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GPIO

Signal

Sampling Window

Output

From Qualifier

SYSCLKOUT

QUALPRD = 1

(SYSCLKOUT/2)

See Note (A)

Sampling period, determined by GPxQUAL

[QUALPRD]

(SYSCLKOUT cycle x 2 x QUALPRD) x 5

TMS320F2810, TMS320F2811, TMS320F2812

TMS320C2810, TMS320C2811, TMS320C2812

www.ti.com

SPRS174S – APRIL 2001 – REVISED MARCH 2011

6.19 General-Purpose Input/Output (GPIO) – Input Timing

This glitch is ignored by the input qualifier. The QUALPRD bit field specifies the qualification sampling period. It can

vary from 00 to 0xFF. Input qualification is not applicable when QUALPRD = 00. For any other value “n”, the

qualification sampling period is 2n SYSCLKOUT cycles (i.e., at every 2n SYSCLKOUT cycle, the GPIO pin will be

sampled). Six consecutive samples must be of the same value for a given input to be recognized.

For the qualifier to detect the change, the input must be stable for 10 SYSCLKOUT cycles or greater. In other words,

the inputs should be stable for (5 × QUALPRD × 2) SYSCLKOUT cycles. This would enable five sampling periods for

detection to occur. Since external signals are driven asynchronously, a 13-SYSCLKOUT-wide pulse provides reliable

recognition.

Figure 6-24. GPIO Input Qualifier – Example Diagram for QUALPRD = 1

Electrical Specifications

115

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TMS320F2811PBKA 数据表(PDF) 115 Page - Texas Instruments