AN2153 Freescale Semiconductor / Motorola, AN2153 Datasheet - Page 4

• Manufacturer Part Number: AN2153
• Description: A Serial Bootloader for Reprogramming the MC9S12DP256 FLASH Memory
• Manufacturer: Freescale Semiconductor / Motorola

Application Note
FLASH Control
Registers
4
The programming voltage required to program and erase the FLASH is
generated internally by on-chip charge pumps. Program and erase
operations are performed by a command driven interface from the
microcontroller using an internal state machine. The completion of a
program or erase operation is signaled by the setting of the CCIF flag
and may optionally generate an interrupt. All FLASH blocks can be
programmed or erased at the same time; however, it is not possible to
read from a FLASH block while it is being erased or programmed.
Each 64-K block contains hardware interlocks which protect data from
accidental corruption. As shown in
zero can be accessed through the 16-Kbyte PPAGE window or at two
fixed address 16-K address ranges. One protected area is located in the
upper address area of the fixed page address range from $C000–$FFFF
and is normally used for bootloader code. Another area is located in the
lower portion of the fixed page address range from $4000–$7FFF.
Additional protected memory areas are present in the three remaining
64-K FLASH blocks; however, they are only accessible through the 16-K
PPAGE window.
The control and status registers for all four FLASH blocks occupy
16 bytes in the input/output (I/O) register area. To accommodate the four
FLASH blocks while occupying a minimum of register address space,
the FLASH control register address range is divided into two sections.
The first four registers, as shown in
blocks. The remaining 12 bytes of the register space have duplicate sets
of registers, one for each FLASH bank. The active register bank is
selected by the BKSEL bits in the unbanked FLASH configuration
register (FCNFG). Note that only three of the banked registers contain
usable status and control bits; the remaining nine registers are reserved
for factory testing or are unused.
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Figure
Figure
1, the upper 32 K of block
2, apply to all four memory
MOTOROLA
AN2153