P89LPC901 View Datasheet(PDF) - Philips Electronics

Part Name

Description

Manufacturer

P89LPC901

8-bit microcontrollers with two-clock 80C51 core 1 kB 3 V Flash with 128-byte RAM

Philips Electronics 

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Table 8: P89LPC902 Special function registers…continued

* indicates SFRs that are bit addressable.

Name

Description

SFR

addr.

MSB

Bit functions and addresses

LSB

Reset value

Hex Binary

Bit address 8F

8E

8D

8C

8B

8A

89

88

TCON* Timer 0 and 1 control

88H TF1

TR1

TF0

TR0

-

-

-

-

00 00000000

TH0

Timer 0 HIGH

8CH

00 00000000

TH1

Timer 1 HIGH

8DH

00 00000000

TL0

Timer 0 LOW

8AH

00 00000000

TL1

Timer 1 LOW

8BH

00 00000000

TMOD

Timer 0 and 1 mode

89H

-

-

T1M1 T1M0

-

-

T0M1 T0M0 00 00000000

TRIM

Internal oscillator trim register 96H

-

-

TRIM.5 TRIM.4 TRIM.3 TRIM.2 TRIM.1 TRIM.0 [5] [6]

WDCON Watchdog control register

A7H PRE2 PRE1 PRE0

-

-

WDRUN WDTOF WDCLK [4] [6]

WDL

Watchdog load

C1H

FF 11111111

WFEED1 Watchdog feed 1

C2H

WFEED2 Watchdog feed 2

C3H

[1] All ports are in input only (high impedance) state after power-up.

[2] BRGR1 and BRGR0 must only be written if BRGEN in BRGCON SFR is ‘0’. If any are written while BRGEN = 1, the result is unpredictable.

Unimplemented bits in SFRs (labeled ’-’) are X (unknown) at all times. Unless otherwise specified, ones should not be written to these bits since they may be used for other

purposes in future derivatives. The reset values shown for these bits are ‘0’s although they are unknown when read.

[3] The RSTSRC register reflects the cause of the P89LPC901/902/903 reset. Upon a power-up reset, all reset source flags are cleared except POF and BOF; the power-on reset

value is xx110000.

[4] After reset, the value is 111001x1, i.e., PRE2-PRE0 are all ‘1’, WDRUN = 1 and WDCLK = 1. WDTOF bit is ‘1’ after Watchdog reset and is ‘0’ after power-on reset. Other resets will

not affect WDTOF.

[5] On power-on reset, the TRIM SFR is initialized with a factory preprogrammed value. Other resets will not cause initialization of the TRIM register.

[6] The only reset source that affects these SFRs is power-on reset.

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