p89lpc935fdh NXP Semiconductors, p89lpc935fdh Datasheet - Page 28

• Manufacturer Part Number: p89lpc935fdh
• Description: 8-bit Microcontroller With Accelerated Two-clock 80c51 Core 4 Kb/8 Kb 3 V Byte-erasable Flash With 8-bit A/d Converters
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 15113
Product data sheet
8.12.1 External interrupt inputs
8.11 Data RAM arrangement
8.12 Interrupts
The P89LPC935/936 also has 512 bytes of on-chip data EEPROM that is accessed via
SFRs (see
The 768 bytes of on-chip RAM are organized as shown in
Table 7:
The P89LPC933/934/935/936 uses a four priority level interrupt structure. This allows
great flexibility in controlling the handling of the many interrupt sources. The
P89LPC933/934/935/936 supports 15 interrupt sources: external interrupts 0 and 1,
timers 0 and 1, serial port Tx, serial port Rx, combined serial port Rx/Tx, brownout detect,
watchdog/Real-Time clock, I
EEPROM write/ADC completion.
Each interrupt source can be individually enabled or disabled by setting or clearing a bit in
the interrupt enable registers IEN0 or IEN1. The IEN0 register also contains a global
disable bit, EA, which disables all interrupts.
Each interrupt source can be individually programmed to one of four priority levels by
setting or clearing bits in the interrupt priority registers IP0, IP0H, IP1, and IP1H. An
interrupt service routine in progress can be interrupted by a higher priority interrupt, but
not by another interrupt of the same or lower priority. The highest priority interrupt service
cannot be interrupted by any other interrupt source. If two requests of different priority
levels are pending at the start of an instruction, the request of higher priority level is
serviced.
If requests of the same priority level are pending at the start of an instruction, an internal
polling sequence determines which request is serviced. This is called the arbitration
ranking.
Remark: The arbitration ranking is only used to resolve pending requests of the same
priority level.
The P89LPC933/934/935/936 has two external interrupt inputs as well as the Keypad
Interrupt function. The two interrupt inputs are identical to those present on the standard
80C51 microcontrollers.
Type
DATA
IDATA
XDATA
•
CODE
64 kB of code memory space, accessed as part of program execution and via the
MOVC instruction. The P89LPC933/934/935/936 have 4 KB/8 kB/16 kB of on-chip
Code memory.
On-chip data memory usages
Section 8.27 “Data EEPROM
Data RAM
Memory that can be addressed directly and indirectly
Memory that can be addressed indirectly
Auxiliary (‘External Data’) on-chip memory that is accessed
using the MOVX instructions (P89LPC935/936)
Rev. 06 — 20 June 2005
8-bit microcontroller with accelerated two-clock 80C51 core
2
C-bus, keyboard, comparators 1 and 2, SPI, CCU, data
P89LPC933/934/935/936
(P89LPC935/936)”).
Table
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
7.
Size (bytes)
128
256
512
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