p89lpc972fn NXP Semiconductors, p89lpc972fn Datasheet - Page 44

• Manufacturer Part Number: p89lpc972fn
• Description: 8-bit Microcontroller With Accelerated Two-clock 80c51 Core 2kb/4 Kb/8 Kb Wide-voltage Byte-erasable ?ash
• Manufacturer: NXP Semiconductors

NXP Semiconductors
P89LPC97X_1
Preliminary data sheet
7.29.10 Hardware activation of the bootloader
7.30 User configuration bytes
7.31 User sector security bytes
Remark: Users who wish to use this loader should take precautions to avoid erasing the
1 kB sector that contains this bootloader. Instead, the page erase function can be used to
erase the first eight 64-byte pages located in this sector.
A custom bootloader can be written with the Boot Vector set to the custom bootloader, if
desired.
Table 9.
The bootloader can also be executed by forcing the device into ISP mode during a
power-on sequence (see the P89LPC970/971/972 User manual for specific information).
This has the same effect as having a non-zero status byte. This allows an application to
be built that will normally execute user code but can be manually forced into ISP
operation. If the factory default setting for the boot is changed, it will no longer point to the
factory pre-programmed ISP bootloader code. After programming the flash, the status
byte should be programmed to zero in order to allow execution of the user’s application
code beginning at address 0000H.
Some user-configurable features of the P89LPC970/971/972 must be defined at power-up
and therefore cannot be set by the program after start of execution. These features are
configured through the use of the flash byte UCFG1 and UCFG2. Please see the
P89LPC970/971/972 User Manual for additional details.
There are four/eight User Sector Security Bytes on the P89LPC970/971/972. Each byte
corresponds to one sector. Please see the P89LPC970/971/972 User manual for
additional details.
Device
P89LPC970
P89LPC971
P89LPC972
Default boot vector values and ISP entry points
Default
boot vector
07H
0FH
1FH
Rev. 01 — 17 December 2009
8-bit microcontroller with accelerated two-clock 80C51 core
Default
bootloader
entry point
0700H
0F00H
1F00H
P89LPC970/971/972
Default bootloader
code range
0600H to 07FFH
0E00H to 1FFFH
1E00H to 1FFFH
© NXP B.V. 2009. All rights reserved.
1 kB sector
range
0400H to 07FFH
0C00H to 0FFFH
1C00H to 1FFFH
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