12

ATSAM2133B

2694A–DRMSD–05/03

Timings

All timing conditions: V

load capacitance = 30 pF.

All timings refer to t

The internal master clock frequency is four times the frequency at pin X1. Therefore t

CK

= t

The sampling rate is given by 1/(t

quency at X1 is 12.288 MHz (48 kHz sampling rate).

Crystal Frequency

Selection

There is a trade-off between the crystal frequency and the support of widely-available

external ROM/Flash components. Table 8 gives information on selecting the best fit for

a given application.

Using 11.2896 MHz crystal frequency allows the use of widely-available ROMs with 100

ns access time while providing state-of-the-art 44.1 kHz sampling rate.

Table 8. Crystal Frequency Selection Parameters

Sample Rate (KHz)

Crystal

(MHz)

t

CK

(ns)

ROM t

A

(ns)

Comments

48

12.288

20.35

92

Maximum frequency

44.1

11.2896

22.14

101

Recommended for current designs

37.5

9.60

26.04

120

31.25

8.00

31.25

146