Datasheet

FLASH Memory (FLASH)
Technical Data MC68HC908LJ12 — Rev. 2.1
62 FLASH Memory (FLASH) Freescale Semiconductor
4.3 Functional Description
The FLASH memory consists of an array of 12,288 bytes for user
memory plus a block of 48 bytes for user interrupt vectors. An erased bit
reads as logic 1 and a programmed bit reads as a logic 0. The FLASH
memory page size is defined as 128 bytes, and is the minimum size that
can be erased in a page erase operation. Program and erase operations
are facilitated through control bits in FLASH control register (FLCR). The
address ranges for the FLASH memory are:
• $C000–$EFFF; user memory; 12,288 bytes
• $FFD0–$FFFF; user interrupt vectors; 48 bytes
Programming tools are available from Freescale. Contact your local
Freescale representative for more information.
NOTE: A security feature prevents viewing of the FLASH contents.
1
Addr.Register Name Bit 7654321Bit 0
$FE08
FLASH Control Register
(FLCR)
Read: 0000
HVEN MASS ERASE PGM
Write:
Reset:00000000
$FE09
FLASH Block Protect
Register
(FLBPR)
Read:
BPR7 BPR6 BPR5 BPR4 BPR3 BPR2 BPR1 BPR0
Write:
Reset:00000000
= Unimplemented
Figure 4-1. FLASH I/O Register Summary
1. No security feature is absolutely secure. However, Freescale’s strategy is to make reading or
copying the FLASH difficult for unauthorized users.