PIC18F66K22-I Datasheet, PDF (125/550 Pages) Microchip Technology – PIC18F87K22 Family Data Sheet

PIC18F87K22 FAMILY
8.6.1 16-BIT BYTE WRITE MODE
Figure 8-1 shows an example of 16-Bit Byte Write
mode for PIC18F87K22 family devices. This mode is
used for two separate 8-bit memories connected for
16-bit operation. This generally includes basic EPROM
and Flash devices. It allows table writes to byte-wide
external memories.
During a TBLWT instruction cycle, the TABLAT data is
presented on the upper and lower bytes of the
AD<15:0> bus. The appropriate WRH or WRL control
line is strobed on the LSb of the TBLPTR.
FIGURE 8-1:
16-BIT BYTE WRITE MODE EXAMPLE
D<7:0>
PIC18F87K22
AD<7:0>
AD<15:8>
ALE
A<19:16>⁽¹⁾
CE
OE
WRH
WRL
373
A<19:0>
D<15:8>
373
(MSB)
A<x:0>
D<7:0>
CE
OE WR⁽²⁾
(LSB)
A<x:0>
D<7:0>
D<7:0>
CE
OE WR⁽²⁾
Address Bus
Data Bus
Control Lines
Note 1: Upper order address lines are used only for 20-bit address widths.
2: This signal only applies to table writes. See Section 7.1 “Table Reads and Table Writes”.
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DS39960D-page 125