Zilog ZUSBOPTS - Manual (Page 337)

UM017105-0511 Program Configurations
Zilog Developer Studio II – ZNEO™
User Manual
309
The start-up code (which is provided in the form of both source code and the standard,
precompiled C start-up module) is downloaded to ROM, and the rest of the executable
program code is downloaded to EROM. The ROM/EROM data (declared using the
_Rom
or _Erom keywords in a C application or appropriate SEGMENT directives in an assem-
bly application) are downloaded into their respective address spaces. The initialized val-
ues of all initialized RAM/ERAM data are also downloaded into EROM. The Flash option
bytes and the vector table are downloaded into ROM at addresses appropriate for the spec-
ified device. The start-up module code is executed from ROM, while the rest of the exe-
cutable program code is executed from EROM. The start-up code sets up the external
interface if required, based on the target setup parameters (see
Setup – see page 76), and
copies the initial values of RAM/ERAM data from EROM to their respective run-time
addresses in RAM/ERAM.
Figure 132. Programmer’s Model—Default Program Configuration
Code
EROM Data
Copy of ERAM Initializers
Copy of RAM Initializers
16-Bit
Addressable
16-Bit
Addressable
Address
IODATA
ERAM
ROM
RAM
EROM
I/O Access
Small Model Stack
RAM Data
Large Model Stack
ERAM Data
ROM Data
Start-up code
Vector Table
Option Bytes
Contents
Range (Space)
(Data)
(Data)