CPC314
C P C 3 1 4 U s e r M a n u a l
40
© 2 0 2 1 F a s t w e l V e r . 0 0 1
2.5 Memory address space
Table 2-4
– Addresses of memory devices
Address
Device
Notes
00000
– 9FFFFh
DOS
DOS Area 640 Kbyte
A0000
– BFFFFh
VGA
Video memory area 128 Kbyte
C0000
– C7FFFh
VGA BIOS
VGA BIOS 32 Kbyte
C8000
– DFFFFh
–
–
E0000
– EFFFFh
System BIOS
Extended System BIOS area 64 Kbyte (16 Kbyte х 4)
F0000
– FFFFFh
System BIOS
System BIOS area 64 Kbyte
Address
Device
Notes
10 0000
– MEMORY TOP *
DRAM
DDR3 SDRAM
MEMORY TOP *
– FFE0 0000
PCI
PCI
FFE0 0000
– FFFF FFFFh
High BIOS
High BIOS Area 2 Mbyte (mapped to PCI)
* Installed DDR3 SDRAM
– 2 GB.
2.6
Using the processor’s GPIO ports
The Vortex86DX3 microchip has 10 x GPIO (General Purpose Input Output) I/O ports, available to
the user through the internal registers of the microchip. Each port has 8 x I/O lines, each of which
can be configured as input or output by programming the registers of the corresponding port.
For working with GPIO ports, 2 x 8-bit registers are used per port - a data register and a direction
register. Each bit of the data register is mapped to the corresponding circuit on the board: bit 0
corresponds to the port 0 line (GPIO_Px0), bit 7 corresponds to the port 7 line (GPIO_P
х7), etc.
Each bit of the direction register is mapped to the corresponding circuit on the board: bit 0
corresponds to the port 0 line (GPIO_Px0), bit 7 corresponds to the port 7 line (GPIO_P
х7), etc.
Table 2-5
– GPIO control registers
GPIO_P2
GPIO_P7
Description
Data register
0x7Ah
0x179h
Direction register
0x9Ah
0x199h
0: Line is input
1: Line is output
Assigning the used GPIO ports is described in the table below.
