5/7

STR71x MEMORY MAPPING AND DEVELOPMENT TOOLSET

2 CODE INITIALIZATION

Before entering the C code, the RW region must be copied from the load region to the execu-

tion region and the ZI region must be created.

The initialization code is integrated in the startup routine "71x_init.s".

The following software is a typical initialization code that corresponds to the last examples. It

uses the symbols generated by the linker to find information about each region.

IMPORT IImage$$RAM$$BaseI

; Base of RAM to initialise

IMPORT ILoad$$RAM$$BaseI

; End of ROM code (=start of ROM data)

IMPORT IImage$$RAM$$ZI$$BaseI

; Base of area to zero initialise

IMPORT IImage$$RAM$$ZI$$LengthI

; Length of area to zero initialise

LDR

r0, =ILoad$$RAM$$BaseI

; Get pointer to ROM data

LDR

r1, =IImage$$RAM$$BaseI

; and RAM copy

LDR

r3, =IImage$$RAM$$ZI$$BaseI

; Zero init base => top of initialised data

CMP

r0, r1

; Check that they are different

BEQ

%F1

0

CMP

r1, r3

; Copy init data

LDRCC

r2, [r0], #4

STRCC

r2, [r1], #4

BCC

%B0

1

LDR

r1, =IImage$$RAM$$ZI$$LengthI; Length of zero init segment

ADD

r1, r1, r3

; Top of zero init segment

MOV

r2, #0

2

CMP

r3, r1

; Zero init

STRCC

r2, [r3], #4

BCC

%B2

If the execution region is mapped the the external memory, before the code initialization, the

EMI must be enabled and configured. The following assembly code enable and configure the

EIM bank 1 with 7 wait states and 16 bit wide.

LDR

r0, =GPIO2_Base_addr

; Configure P2.0 -> 3 in AF_PP mode

LDR

r1, =0x0000000F

STR

r1, [r0, #PC0_off_addr]

STR

r1, [r0, #PC1_off_addr]

STR

r1, [r0, #PC2_off_addr]

LDR

r0, =EMI_Base_addr

LDR

r1, =0x0000803D

STR

r1, [r0, #BCON1_off_addr]

; Enable bank 1 16-bit 7 wait state