AT89C5132-ROTUL datasheet(63/182 Pages) ATMEL

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4173E–USB–09/07

AT89C5132

Table 50. Sample Duplication Factor

14.5

Interrupt Request

The audio interrupt request can be generated by two sources when in C51 audio mode: a sam-

ple request when SREQ flag in AUDSTA register is set to logic 1, and an under-run condition

when UDRN flag in AUDSTA register is set to logic 1. Both sources can be enabled separately

by masking one of them using the MSREQ and MUDRN bits in AUDCON1 register. A global

enable of the audio interface is provided by setting the EAUD bit in IEN0 register.

The interrupt is requested each time one of the two sources is set to one. The source flags are

cleared by writing some data in the audio buffer through AUDDAT, but the global audio interrupt

flag is cleared by hardware when the interrupt service routine is executed.

Figure 14-5. Audio Interface Interrupt System

14.6

Voice or Sound Playing

In voice or sound playing mode, the operations required are to configure the PLL and the audio

interface according to the DAC selected. The audio clock is programmed to generate the 256·Fs

or 384·Fs. The data flow sent by the C51 is then regulated by interrupt and data is loaded 4

Bytes by 4 Bytes. Figure 14-6 shows the configuration flow of the audio interface when in voice

or sound mode.

DUP1

DUP0

Factor

No sample duplication, DAC rate = 8 kHz (C51 rate).

One sample duplication, DAC rate = 16 kHz (2 x C51 rate).

Two samples duplication, DAC rate = 32 kHz (4 x C51 rate).

Three samples duplication, DAC rate = 48 kHz (6 x C51 rate).

SREQ

AUDSTA.7

Audio

Interrupt

Request

UDRN

AUDSTA.6

MSREQ

AUDCON1.5

EAUD

IEN0.6

MUDRN

AUDCON1.4

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