SAF-XC886-6FFI 查看數據表（PDF） - Infineon Technologies

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产品描述 (功能)

比赛名单

SAF-XC886-6FFI

8-Bit Single-Chip Microcontroller

Infineon Technologies 

XC886/888CLM

Functional Description

In order to access a register located in a page different from the actual one, the current

page must be left. This is done by reprogramming the bit field PAGE in the page register.

Only then can the desired access be performed.

If an interrupt routine is initiated between the page register access and the module

register access, and the interrupt needs to access a register located in another page, the

current page setting can be saved, the new one programmed and finally, the old page

setting restored. This is possible with the storage fields STx (x = 0 - 3) for the save and

restore action of the current page setting. By indicating which storage bit field should be

used in parallel with the new page value, a single write operation can:

• Save the contents of PAGE in STx before overwriting with the new value

(this is done in the beginning of the interrupt routine to save the current page setting

and program the new page number); or

• Overwrite the contents of PAGE with the contents of STx, ignoring the value written to

the bit positions of PAGE

(this is done at the end of the interrupt routine to restore the previous page setting

before the interrupt occurred)

ST3

ST2

ST1

ST0

STNR

value update

from CPU

PAGE

Figure 10 Storage Elements for Paging

With this mechanism, a certain number of interrupt routines (or other routines) can

perform page changes without reading and storing the previously used page information.

The use of only write operations makes the system simpler and faster. Consequently,

this mechanism significantly improves the performance of short interrupt routines.

The XC886/888 supports local address extension for:

• Parallel Ports

• Analog-to-Digital Converter (ADC)

• Capture/Compare Unit 6 (CCU6)

• System Control Registers

Data Sheet

Prelimary

24

V0.1, 2006-02

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