AT80SND1C-ROTIL datasheet(142/210 Pages) ATMEL

Part #	AT80SND1C-ROTIL

Description	Single-Chip Flash Microcontroller with MP3 Decoder and Human Interface

PDF	210 Pages

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Manufacturer	ATMEL [ATMEL Corporation]

Direct Link	http://www.atmel.com

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142 / 210 page

142

AT8xC51SND1C

4109E–8051–06/03

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 109 these

flags are combined together to appear as a single interrupt source for the C51 core.

Flags must be cleared by software when executing the serial interrupt service routine.

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

are globally enabled by setting EA bit in IEN0 register.

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

disabled, RI flag is set during the stop bit or during the ninth bit as detailed in Figure 110.

Figure 109. Serial I/O Interrupt System

Figure 110. Interrupt Waveforms

IEN0.4

Serial I/O

Interrupt Request

SCON.1

SCON.0

RXD

D1D2D3D4

D5D6

Start Bit

8-bit Data

Stop Bit

SMOD0 = X

SMOD0 = 1

a. Mode 1

b. Mode 2 and 3

RXD

D1D2D3D4

D5D6

Start bit

9-bit data

Stop bit

SMOD0 = 1

SMOD0 = 0

AT80SND1C-ROTIL Datasheet(PDF) 142 Page - ATMEL Corporation