Cypress Semiconductor EZ-Host CY7C67300 User Manual download pdf (Page 28)

CY7C6730

PRELIMINARY

Document #: 38-08015 Rev. *D Page 28 of 120

6.0 Memory Map

6.1 Mapping

The EZ-Host has 64K bytes of total addressable memory containing both program and data space. This memory space is byte

addressable. Figure 6-1 shows the various memory region address locations.

6.1.1 Internal Memory

Of the internal memory, 15K bytes is allocated for user’s program and data code. The lower memory space from 0x0000 to 0x0600

is reserved for interrupt vectors, general purpose registers, USB control registers, the stack, and other BIOS variables. The upper

internal memory space contains EZ-Host control registers from 0xC000 to 0xC0FF and the BIOS ROM itself from 0xE000 to

0xFFFF. For more information on the reserved lower memory or the BIOS ROM, please refer to the Programmers documentation

and the BIOS documentation.

During development with the EZ-Host toolset, the lower 1K byte of User’s space (0x0600 to 0x0A00) should be left available to

load the GDB stub. The GDB stub is required to allow the toolset debug access into EZ-Host.

6.1.2 External Memory

An external memory interface allows for additional program and data space to be added. 8K bytes of this space is reserved as

directly addressable external RAM for data. 16K bytes of the external memory space is addressable through two Extended Page

Map registers [0xC018, 0xC01A]. This 16K byte region of external memory can be configured to interface with either SRAM or

ROM through the External Memory Control Register [0xC03A]. This 16K region can be broken into two 8K regions, each of which

can be configured as SRAM or ROM.

The upper external memory space at 0xC100 is reserved for directly addressable external ROM. This allows for program code

to be stored and booted from an external ROM. Please refer to BIOS documentation for additional information on booting.

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Cypress Semiconductor EZ-Host CY7C67300 User Manual Page 28