mc68hc908gp32 Freescale Semiconductor, Inc, mc68hc908gp32 Datasheet - Page 39

• Manufacturer Part Number: mc68hc908gp32
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

2.6.2 FLASH Control Register
The FLASH control register (FLCR) controls FLASH program and erase operations.
HVEN — High-Voltage Enable Bit
MASS — Mass Erase Control Bit
ERASE — Erase Control Bit
PGM — Program Control Bit
2.6.3 FLASH Page Erase Operation
Use this step-by-step procedure to erase a page (128 bytes) of FLASH memory.
1. No security feature is absolutely secure. However, Freescale’s strategy is to make reading or copying the FLASH difficult for
Freescale Semiconductor
unauthorized users.
1. Set the ERASE bit, and clear the MASS bit in the FLASH control register.
2. Read the FLASH block protect register.
3. Write any data to any FLASH location within the page address range of the block to be erased.
4. Wait for a time, t
5. Set the HVEN bit.
This read/write bit enables the charge pump to drive high voltages for program and erase operations
in the array. HVEN can only be set if either PGM = 1 or ERASE = 1 and the proper sequence for
program or erase is followed.
Setting this read/write bit configures the 32Kbyte FLASH array for mass erase operation.
This read/write bit configures the memory for erase operation. ERASE is interlocked with the PGM bit
such that both bits cannot be equal to 1 or set to 1 at the same time.
This read/write bit configures the memory for program operation. PGM is interlocked with the ERASE
bit such that both bits cannot be equal to 1 or set to 1 at the same time.
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 = PAGE erase operation selected
1 = Erase operation selected
0 = Erase operation unselected
1 = Program operation selected
0 = Program operation unselected
Address:
A security feature prevents viewing of the FLASH contents.
Reset:
Read:
Write:
$FE08
nvs
Bit 7
0
0
(min. 10 µs)
Figure 2-3. FLASH Control Register (FLCR)
= Unimplemented
6
0
0
MC68HC908GP32 Data Sheet, Rev. 10
5
0
0
NOTE
4
0
0
HVEN
3
0
MASS
2
0
(1)
ERASE
1
0
PGM
Bit 0
0
FLASH Memory
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