P89LPC915_916_917 NXP Semiconductors, P89LPC915_916_917 Datasheet - Page 33

• Manufacturer Part Number: P89LPC915_916_917
• Description: The P89LPC915/916/917 are single-chip microcontrollers, available in low-cost packages,based on a high performance processor architecture that executes instructions in two tofour clocks, six times the rate of standard 80C51 devices
• Manufacturer: NXP Semiconductors

NXP Semiconductors
P89LPC915_916_917_5
Product data sheet
8.10 Memory organization
8.11 Data RAM arrangement
8.12 Interrupts
8.9 Low power select
The P89LPC915/916/917 is designed to run at 18 MHz (CCLK) maximum. However, if
CCLK is 8 MHz or slower, the CLKLP SFR bit (AUXR1.7) can be set to ‘1’ to lower the
power consumption further. On any reset, CLKLP is ‘0’ allowing highest performance
access. This bit can then be set in software if CCLK is running at 8 MHz or slower.
The various P89LPC915/916/917 memory spaces are as follows:
The 256 bytes of on-chip RAM are organized as shown in
Table 10.
The P89LPC915/916/917 uses a four priority level interrupt structure. This allows great
flexibility in controlling the handling of the many interrupt sources.
The P89LPC915 and P89LPC917 support 13 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/RTC, I
The P89LPC916 supports 14 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/RTC, I
Type
DATA
IDATA
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DATA
128 bytes of internal data memory space (00H:7FH) accessed via direct or indirect
addressing, using instructions other than MOVX and MOVC. All or part of the Stack
may be in this area.
IDATA
Indirect Data. 256 bytes of internal data memory space (00H:FFH) accessed via
indirect addressing using instructions other than MOVX and MOVC. All or part of the
Stack may be in this area. This area includes the DATA area and the 128 bytes
immediately above it.
SFR
Special Function Registers. Selected CPU registers and peripheral control and status
registers, accessible only via direct addressing.
CODE
64 kB of Code memory space, accessed as part of program execution and via the
MOVC instruction. The P89LPC915/916/917 devices have 2 kB of on-chip Code
memory.
On-chip data memory usages
Data RAM
Memory that can be addressed directly and indirectly
Memory that can be addressed indirectly
2
C-bus, keyboard, comparators 1 and 2, SPI, and ADC completion.
Rev. 05 — 15 December 2009
2
8-bit microcontrollers with accelerated two-clock 80C51 core
C-bus, keyboard, comparators 1 and 2, and ADC completion.
P89LPC915/916/917
Table
10.
© NXP B.V. 2009. All rights reserved.
Size (bytes)
128
256
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