C517A_99 Datasheet, PDF (32/218 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

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C517A
Port 0
Address/Data
XPAGE
Write to Port 2
XRAM
Port 2
Page Address
MCB02112
Figure 3-2
Write Page Address to Port 2
“MOV P2,pageaddress“ will write the page address to Port 2 and the XPAGE-Register.
When external RAM is to be accessed in the XRAM address range (F800H - FFFFH), XRAM has
to be disabled. When additional external RAM is to be addressed in an address range < F800H,
XRAM may remain enabled and there is no need to overwrite XPAGE by a second move.
Semiconductor Group
3-6