mc68hc908qf4 Freescale Semiconductor, Inc, mc68hc908qf4 Datasheet - Page 30

• Manufacturer Part Number: mc68hc908qf4
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Memory
2.6 FLASH Memory (FLASH)
2.6.1 FLASH Control Register
Data Sheet
30
NOTE:
This subsection describes the operation of the embedded FLASH memory. The
FLASH 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 memory consists of an array of 4096 bytes with an additional 48 bytes
for user vectors. The minimum size of FLASH memory that can be erased is 64
bytes; and the maximum size of FLASH memory that can be programmed in a
program cycle is 32 bytes (a row). Program and erase operations are facilitated
through control bits in the FLASH control register (FLCR). Details for these
operations appear later in this section. The address ranges for the user memory
and vectors are:
An erased bit reads as 1 and a programmed bit reads as 0. A security feature
prevents viewing of the FLASH contents.
The FLASH control register (FLCR) controls FLASH program and erase
operations.
HVEN — High Voltage Enable Bit
MASS — Mass Erase Control Bit
1. No security feature is absolutely secure. However, Motorola’s strategy is to make reading or
copying the FLASH difficult for unauthorized users.
•
•
This read/write bit enables high voltage from the charge pump to the memory
for either program or erase operation. It can only be set if either PGM =1 or
ERASE =1 and the proper sequence for program or erase is followed.
This read/write bit configures the memory for mass erase operation.
Address:
Reset:
Read:
Write:
1 = High voltage enabled to array and charge pump on
0 = High voltage disabled to array and charge pump off
1 = Mass erase operation selected
0 = Mass erase operation unselected
$EE00 – $FDFF; user memory, 4096 bytes
$FFD0 – $FFFF; user interrupt vectors, 48 bytes.
Freescale Semiconductor, Inc.
For More Information On This Product,
$FE08
Bit 7
0
0
Go to: www.freescale.com
Figure 2-3. FLASH Control Register (FLCR)
= Unimplemented
6
0
0
Memory
5
0
0
(1)
4
0
0
HVEN
3
0
MASS
MC68HC908QF4 — Rev. 1.0
2
0
ERASE
1
0
MOTOROLA
PGM
Bit 0
0