Freescale Semiconductor MC68HC908MR32 Manual Do Utilizador

Freescale Semiconductor

37

The 240 bytes at addresses $FE10–$FEFF are reserved ROM addresses that contain the instructions for 
the monitor functions. See 

Addresses $0060–$035F are RAM locations. The location of the stack RAM is programmable. The 16-bit 
stack pointer allows the stack to be anywhere in the 64-Kbyte memory space.

Within page zero are 160 bytes of RAM. Because the location of the stack RAM is programmable, all page 
zero RAM locations can be used for input/output (I/O) control and user data or code. When the stack 
pointer is moved from its reset location at $00FF, direct addressing mode instructions can access 
efficiently all page zero RAM locations. Page zero RAM, therefore, provides ideal locations for frequently 
accessed global variables.

Before processing an interrupt, the central processor unit (CPU) uses five bytes of the stack to save the 
contents of the CPU registers.

$FFEE

PWMMC vector (high)

$FFEF

PWMMC vector (low)

$FFF0

FAULT 4 (high)

$FFF1

FAULT 4 (low)

$FFF2

FAULT 3 (high)

$FFF3

FAULT 3 (low)

$FFF4

FAULT 2 (high)

$FFF5

FAULT 2 (low)

$FFF6

FAULT 1 (high)

$FFF7

FAULT 1 (low)

$FFF8

PLL vector (high)

$FFF9

PLL vector (low)

$FFFA

IRQ vector (high)

$FFFB

IRQ vector (low)

$FFFC

SWI vector (high)

$FFFD

SWI vector (low)

$FFFE

Reset vector (high)

$FFFF

Reset vector (low)