AT83SND2CMP3B datasheet(177/241 Pages) ATMEL

Part #	AT83SND2CMP3B

Description	Single-Chip Flash Microcontroller with MP3 Decoder with Full Audio Interface

PDF	241 Pages

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Manufacturer	ATMEL [ATMEL Corporation]

Direct Link	http://www.atmel.com

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177

4341F–MP3–03/06

AT8xC51SND2C/MP3B

20.7

Interrupt

The Serial I/O Port handles 2 interrupt sources that are the “end of reception” (RI in SCON) and

“end of transmission” (TI in SCON) flags. As shown in Figure 20-16 these flags are combined

together to appear as a single interrupt source for the C51 core. Flags must be cleared by soft-

ware when executing the serial interrupt service routine.

The serial interrupt is enabled by setting ES bit in IEN0 register. This assumes interrupts are glo-

bally enabled by setting EA bit in IEN0 register.

Depending on the selected mode and weather the framing error detection is enabled or dis-

abled, RI flag is set during the stop bit or during the ninth bit as detailed in Figure 20-17.

Figure 20-16. Serial I/O Interrupt System

Figure 20-17. Interrupt Waveforms

IEN0.4

Serial I/O

Interrupt Request

SCON.1

SCON.0

RXD

D1D2D3D4D5D6D7

Start Bit

8-bit Data

Stop Bit

SMOD0 = X

SMOD0 = 1

a. Mode 1

b. Mode 2 and 3

RXD

D1D2D3D4D5D6

Start bit

9-bit data

Stop bit

SMOD0 = 1

SMOD0 = 0

AT83SND2CMP3B Datasheet(PDF) 177 Page - ATMEL Corporation