P89LPC901 PHILIPS [NXP Semiconductors], P89LPC901 Datasheet - Page 17

• Manufacturer Part Number: P89LPC901
• Description: 8-bit microcontrollers with two-clock 80C51 core 1 kB 3 V Flash with 128-byte RAM
• Manufacturer: PHILIPS [NXP Semiconductors]

Table 7:
* indicates SFRs that are bit addressable.
[1]
[2]
[3]
[4]
[5]
[6]
Name
TCON*
TH0
TH1
TL0
TL1
TMOD
TRIM
WDCON
WDL
WFEED1
WFEED2
All ports are in input only (high impedance) state after power-up.
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.
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.
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.
On power-on reset, the TRIM SFR is initialized with a factory preprogrammed value. Other resets will not cause initialization of the TRIM register.
The only reset source that affects these SFRs is power-on reset.
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P89LPC901 Special function registers
Description
Timer 0 and 1 control
Timer 0 HIGH
Timer 1 HIGH
Timer 0 LOW
Timer 1 LOW
Timer 0 and 1 mode
Internal oscillator trim register
Watchdog control register
Watchdog load
Watchdog feed 1
Watchdog feed 2
Bit address
SFR
addr.
8CH
8DH
8AH
8BH
A7H
C1H
C2H
C3H
88H
89H
96H
…continued
PRE2
MSB
TF1
8F
-
-
PRE1
TR1
8E
-
-
TRIM.5
T1M1
PRE0
TF0
8D
Bit functions and addresses
TRIM.4
T1M0
TR0
8C
-
TRIM.3
8B
-
-
-
WDRUN
TRIM.2
8A
-
-
WDTOF
TRIM.1
T0M1
89
-
WDCLK
TRIM.0
T0M0
LSB
88
-
Reset value
Hex
00
00
00
00
00
00
[5] [6]
[4] [6]
FF
Binary
00000000
00000000
00000000
00000000
00000000
00000000
11111111