saf-xc888cm-8ffi5v Infineon Technologies Corporation, saf-xc888cm-8ffi5v Datasheet - Page 33

• Manufacturer Part Number: saf-xc888cm-8ffi5v
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Infineon Technologies Corporation

Figure 9
In order to access a register located in a page different from the actual one, the current
page must be exited. 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 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:
•
Data Sheet
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
Address Extension by Paging
(to/from CPU)
SFR Address
(from CPU)
SFR Data
rw
MOD_PAGE.PAGE
26
Module
SFR0
SFR1
SFRx
SFR0
SFR1
SFRy
SFR0
SFR1
SFRz
Functional Description
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XC886/888CLM
V1.1, 2009-01