Philips Semiconductors

Product specification

80C550/83C550/87C550

80C51 8-bit microcontroller family

4K/128 OTP/ROM/ROMless, 8 channel 8 bit A/D, watchdog timer

1998 May 01

7

SMOD

SIDL

X

X

GF1

GF0

PD

IDL

LSB

MSB

NOTE:

The PCON register is at SFR byte address 87H. Its contents following a reset are 00XX0000.

BIT

SYMBOL

FUNCTION

PCON.7

SMOD

Double baud rate

PCON.6

SIDL

Serial port idle

PCON.5

X

Reserved for future use

PCON.4

X

Reserved for future use

PCON.3

GF1

General purpose flag bit

PCON.2

GF0

General purpose flag bit

PCON.1

PD

Power down bit

PCON.0

IDL

Idle mode bit

SU00197

Figure 1. Power Control Register (PCON)

XX

X

ADCI

ADCS AADR2 AADR1 AADR0

LSB

MSB

BIT

SYMBOL

FUNCTION

ADCON.7 —

Not used

ADCON.6 —

Not used

ADCON.5 —

Not used

ADCON.4 ADCI

ADC Interrupt flag.

This flag is set when an ADC conversion result is ready to be read. An interrupt is invoked if the

A/D interrupt is enabled. The flag must be cleared by software. It cannot be set by software.

ADCON.3 ADCS

ADC Start and Status.

Setting this flag starts an A/D conversion. The ADC logic insures that this signal is high while the

ADC is busy. On completion of the conversion, ADCS is reset at the same time the interrupt flag

ADCI is set. ADCS cannot be reset by software.

ADCON.2 ADDR2

Analog Input Select 2

ADCON.1 ADDR1

Analog Input Select 1

ADCON.0 ADDR0

Analog Input Select 0

SU00198

INPUT CHANNEL SELECTION

ADDR2

ADDR1

ADDR0

INPUT PIN

0

0

0

ADC0

0

0

1

ADC1

0

1

0

ADC2

0

1

1

ADC3

1

0

0

ADC4

1

0

1

ADC5

1

1

0

ADC6

1

1

1

ADC7

Figure 2. A/D Control Register (ADCON)