MC9S08DV60 Datasheet, PDF (52/414 Pages) Freescale Semiconductor, Inc – HCS08 Microcontrollers

Chapter 4 Memory
4.4 RAM
The MC9S08DV60 Series includes static RAM. The locations in RAM below 0x0100 can be accessed
using the more efficient direct addressing mode, and any single bit in this area can be accessed with the bit
manipulation instructions (BCLR, BSET, BRCLR, and BRSET). Locating the most frequently accessed
program variables in this area of RAM is preferred.
The RAM retains data while the MCU is in low-power wait, stop2, or stop3 mode. At power-on the
contents of RAM are uninitialized. RAM data is unaffected by any reset if the supply voltage does not drop
below the minimum value for RAM retention (V_RAM).
For compatibility with M68HC05 MCUs, the HCS08 resets the stack pointer to 0x00FF. In the
MC9S08DV60 Series, it is usually best to reinitialize the stack pointer to the top of the RAM so the direct
page RAM can be used for frequently accessed RAM variables and bit-addressable program variables.
Include the following 2-instruction sequence in your reset initialization routine (where RamLast is equated
to the highest address of the RAM in the Freescale Semiconductor equate file).
LDHX
TXS
#RamLast+1
;point one past RAM
;SP<-(H:X-1)
When security is enabled, the RAM is considered a secure memory resource and is not accessible through
BDM or code executing from non-secure memory. See Section 4.5.9, “Security”, for a detailed description
of the security feature.
4.5 Flash
MC9S08DV60 Series devices include Flash memory intended primarily for program and data storage.
In-circuit programming allows the operating program and data to be loaded into Flash after final assembly
of the application product. It is possible to program the arrays through the single-wire background debug
interface. Because no special voltages are needed for erase and programming operations, in-application
programming is also possible through other software-controlled communication paths. For a more detailed
discussion of in-circuit and in-application programming, refer to the HCS08 Family Reference Manual,
Volume I, Freescale Semiconductor document order number HCS08RMv1.
4.5.1 Features
Features of the Flash include:
• Array size (see Table 1-1 for exact array sizes)
• Flash sector size: 768 bytes
• Single power supply program and erase
• Command interface for fast program and erase operation
• Up to 100,000 program/erase cycles at typical voltage and temperature
• Flexible block protection and vector redirection
• Security feature for Flash and RAM
• Burst programming capability
• Sector erase abort
MC9S08DV60 Series Data Sheet, Rev 3
52
Freescale Semiconductor