MC908GR32AVFAE Datasheet, PDF (50/314 Pages) Freescale Semiconductor, Inc – Microcontrollers

Memory
2.7 FLASH-2 Memory (FLASH-2)
This subsection describes the operation of the embedded FLASH-2 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.
2.7.1 Functional Description
The FLASH-2 memory is a non-continuous array consisting of a total of 29,822 bytes. An erased bit reads
as a 1 and a programmed bit reads as a 0.
Memory in the FLASH-2 array is organized into rows within pages. There are two rows of memory per
page with 64 bytes per row. The minimum erase block size is a single page,128 bytes. Programming is
performed on a per-row basis, 64 bytes at a time. Program and erase operations are facilitated through
control bits in the FLASH-2 control register (FL2CR). Details for these operations appear later in this
subsection.
The FLASH-2 memory map consists of:
• $0462–$04FF: user memory (158 bytes)
• $0980–$1B7F: user memory (4608 bytes)
• $1E20–$7FFF: user memory (25056 bytes)
• $FF81: FLASH-2 block protect register (FL2BPR)
NOTE
FL2BPR physically resides within FLASH-1 memory addressing space
• $FE08: FLASH-2 control register (FL2CR)
Programming tools are available from Freescale Semiconductor. Contact your local representative for
more information.
NOTE
A security feature prevents viewing of the FLASH contents.⁽¹⁾
2.7.2 FLASH-2 Control and Block Protect Registers
The FLASH-2 array has two registers that control its operation, the FLASH-2 control register (FL2CR) and
the FLASH-2 block protect register (FL2BPR).
2.7.2.1 FLASH-2 Control Register
The FLASH-2 control register (FL2CR) controls FLASH-2 program and erase operations.
Address:
Read:
Write:
Reset:
$FE08
Bit 7
0
0
6
5
0
0
0
0
= Unimplemented
4
3
2
1
Bit 0
0
HVEN MASS ERASE PGM
0
0
0
0
0
Figure 2-7. FLASH-2 Control Register (FL2CR)
1. No security feature is absolutely secure. However, Freescale’s strategy is to make reading or copying the FLASH difficult for
unauthorized users.
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