M68HC08 datasheet(28/188 Pages) FREESCALE

28 / 188 page

Memory

Data Sheet

MC68HC908RF2 — Rev. 4.0

Memory

MOTOROLA

2.4 Random-Access Memory (RAM)

Addresses $0080–$00FF are RAM locations. The location of the stack RAM is

programmable.

NOTE:

For correct operation, the stack pointer must point only to RAM locations.

Before processing an interrupt, the CPU uses five bytes of the stack to save the

contents of the CPU registers.

NOTE:

For M68HC05, M6805, and M146805 compatibility, the H register is not stacked.

During a subroutine call, the CPU uses two bytes of the stack to store the return

address. The stack pointer decrements during pushes and increments during pulls.

NOTE:

Be careful when using nested subroutines. The CPU could overwrite data in the

RAM during a subroutine or during the interrupt stacking operation.

2.5 FLASH 2TS Memory

This section describes the operation of the embedded FLASH 2TS memory. This

memory can be read, programmed, and erased from a single external supply. The

program and erase operations are enabled through the use of an internal charge

pump.

The FLASH 2TS memory is appropriately named to describe its 2-transistor

source-select bit cell. The FLASH 2TS memory is an array of 2031 bytes with an

additional 14 bytes of user vectors and one byte for block protection. An erased bit

reads as a 0 and a programmed bit reads as a 1.

The address ranges for the user memory, control register, and vectors are:

•

$7800–$7FEE, user space

•

$7FEF, reserved — optional ICG trim value, see 6.7.3 ICG Trim Register

•

$FFF0, block protect register

•

$FE08, FLASH 2TS control register

•

$FFF2–$FFFF, these locations are reserved for user-defined interrupt and

reset vectors

This list is the row architecture for the user space array:

$7800–$7807 (Row 0)

$7808–$780F (Row 1)

$7810–$7817 (Row 2)

$7818–$781F (Row 3)

$7820–$7827 (Row 4)

------------------------------------

$7FE8–$7FEF (Row 253)

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

M68HC08 Datasheet(PDF) 28 Page - Freescale Semiconductor, Inc

M68HC08 Datasheet(HTML) 28 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL