Rainbow Electronics T89C51CC02 - Manual (Page 22)

22 Rev.A - May 17, 2001
Preliminary
T89C51CC02
7.3.5. Loading the Column Latches
Any number of data from 1 byte to 128 bytes can be loaded in the column latches. This provides the capability
to program the whole memory by byte, by page or by any number of bytes in a page.
When programming is launched, an automatic erase of the locations loaded in the column latches is first performed,
then programming is effectively done. Thus no page or block erase is needed and only the loaded data are
programmed in the corresponding page.
The following procedure is used to load the column latches and is summarized in Figure 8:
•
Map the column latch space by setting FPS bit.
•
Load the DPTR with the address to load.
•
Load Accumulator register with the data to load.
•
Execute the MOVX @DPTR, A instruction.
•
If needed loop the three last instructions until the page is completely loaded.
Figure 8. Column Latches Loading Procedure
Column Latches
Loading
Data Load
DPTR= Address
ACC= Data
Exec: MOVX @DPTR, A
Last Byte
to load?
Column Latches Mapping
FPS= 1
Data memory Mapping
FPS= 0