P89V51RD2 Philips Semiconductors, P89V51RD2 Datasheet - Page 53

• Manufacturer Part Number: P89V51RD2
• Description: 8-bit 80C51 5 V low power 64 kB Flash microcontroller with 1 kB RAM
• Manufacturer: Philips Semiconductors

Philips Semiconductors
Table 43:
9397 750 12964
Product data
Description
Ext. Int0
Brown-out
T0
Ext. Int1
T1
PCA
UART/SPI
T2
Interrupt polling sequence
Interrupt Flag
IE0
-
TF0
IE1
TF1
CF/CCFn
TI/RI/SPIF
TF2, EXF2
7.10.2 Software reset
7.10.3 Brown-out detection reset
7.10.4 Interrupt priority and polling sequence
The software reset is executed by changing FCF[1] (SWR) from ‘0’ to ‘1’. A software
reset will reset the program counter to address 0000H. All SFR registers will be set to
their reset values, except FCF[1] (SWR), WDTC[2] (WDTS), and RAM data will not
be altered.
The device includes a brown-out detection circuit to protect the system from severed
supplied voltage V
is 3.85 V. For brown-out voltage parameters, please refer to
When V
circuit to generate a brown-out interrupt but the CPU still runs until the supplied
voltage returns to the brown-out detection voltage V
brown-out detection is to cause a processor reset.
V
detection circuit will respond.
Brown-out interrupt can be enabled by setting the EBO bit in IEA register (address
E8H, bit 3). If EBO bit is set and a brown-out condition occurs, a brown-out interrupt
will be generated to execute the program at location 004BH. It is required that the
EBO bit be cleared by software after the brown-out interrupt is serviced. Clearing
EBO bit when the brown-out condition is active will properly reset the device. If
brown-out interrupt is not enabled, a brown-out condition will reset the program to
resume execution at location 0000H.
The device supports eight interrupt sources under a four level priority scheme.
Table 43
SPI serial interface and the UART share the same interrupt vector. (See
DD
must stay below V
Vector
Address
0003H
004BH
000BH
0013H
001BH
0033H
0023H
002BH
DD
summarizes the polling sequence of the supported interrupts. Note that the
drops below this voltage threshold, the brown-out detector triggers the
Rev. 01 — 01 March 2004
DD
Interrupt
Enable
EX0
EBO
ET0
EX1
ET1
EC
ES
ET2
fluctuations. The P89V51RD2’s brown-out detection threshold
BOD
at least four oscillator clock periods before the brown-out
Interrupt
Priority
PX0/H
PBO/H
PT0/H
PX1/H
PT1/H
PPCH
PS/H
PT2/H
8-bit microcontrollers with 80C51 core
BOD
Service
Priority
1 (highest)
2
3
4
5
6
7
8
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
. The default operation for a
P89V51RD2
Table 67
Wake-Up
Power-down
yes
no
no
yes
no
no
no
no
and
Figure
Table
53 of 75
27).
68.