AC164139 Microchip Technology, AC164139 Datasheet - Page 73

• Manufacturer Part Number: AC164139
• Description: Graphics Display Prototype Board Graphics
• Manufacturer: Microchip Technology

Specifications of AC164139

• Main Purpose: LCD Development
• Embedded: No
• Utilized Ic / Part: PICtail™ Plus Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Primary Attributes: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.2.5.2
In order to write data to EDS space, such as in EDS
reads, an Address Pointer is set up by loading the
required EDS page number into the DSWPAG register,
and assigning the offset address to one of the W regis-
ters. Once the above assignment is done, then the
FIGURE 4-6:
When the MSBs of EA is ‘1’, the lower 9 bits of
DSWPAG are concatenated to the lower 15 bits of EA
to form a 24-bit EDS address for write operations.
Example 4-2 shows how to write a byte, word and dou-
ble-word to EDS.
EXAMPLE 4-2:
 2010 Microchip Technology Inc.
; Set the EDS page where the data to be written
;Write a byte to the selected location
;Write a word to the selected location
;Write a Double - word to the selected location
mov
mov
mov
bset
mov
mov
mov.b
mov.b
mov
mov
mov
mov
mov.d
Data Write into EDS Space
#0x0002 , w0
w0 , DSWPAG
#0x0800 ,
w1 , #15
#0x00A5 , w2
#0x003C , w3
w2 , [w1++]
w3 , [w1++]
#0x1234
w2 , [w1]
#0x1122 , w2
#0x4455 , w3
w2 , [w1]
8
EDS ADDRESS GENERATION FOR WRITE OPERATIONS
EDS WRITE CODE IN ASSEMBLY
, w2
DSWPAG Reg
w1
9 Bits
;page 2 is selected for write
;select the location (0x800) to be written
;set the MSB of the base address, enable EDS mode
;write High byte
;
;
;2 EDS writes
Select
;write Low byte
0
1
PIC24FJ256DA210 FAMILY
24-Bit EA
EDS window is enabled by setting bit 15 of the working
register, assigned with the offset address, and the
accessed location can be written.
Figure 4-2 illustrates how the EDS space address is
generated for write operations.
Wn
15 Bits
Wn<0> is Byte Select
DS39969B-page 73