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[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.

[3]

The RSTSRC register reflects the cause of the P89LPC920/921/922 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.

TRIM

Internal oscillator trim register

96H

-

ENCLK

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

Table 4:

* indicates SFRs that are bit addressable.

Name

Description

SFR

addr.

Bit functions and addresses

Reset value

MSB

LSB

Hex

Binary