AN2156 Freescale Semiconductor / Motorola, AN2156 Datasheet - Page 12

• Manufacturer Part Number: AN2156
• Description: Programming and Erasing FLASH and EEPROM Memories on the MC68HC908AS60A/AZ60A
• Manufacturer: Freescale Semiconductor / Motorola

Application Note
FLASH Erase Operations
FLASH Mass Erase Algorithm
12
NOTE:
On the MC68HC908AS60A/AZ60A, the FLASH arrays can be erased
one page (128 bytes) at a time or an entire array can be erased with one
routine (mass erase.) The pages are from addresses $xx00 to $xx7F
and from $xx80 to $xxFF.
flowcharts.
Each FLASH array has separate FLASH control and block protect
registers. Make sure to set the bits in the appropriate register.
1. Set the ERASE bit and the MASS bit in the FLASH control register
2. Read the FLASH block protect register (FLxBPR).
3. Write to any FLASH address within the address range to be
4. Wait for a time, t
5. Set the HVEN bit.
6. Wait for a time, t
7. Clear the ERASE bit.
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(FLxCR).
ERASE = 1 configures the FLASH memory for an erase operation.
MASS = 1 sets the MASS erase operation.
The block protect register must be read before high voltage can be
enabled. If the desired address set in step 3 is in a protected block,
erase will fail.
erased. For mass erase, this is any address in that FLASH array.
The address is used to determine which array will be erased.
Internal high voltage is charged.
Internal high voltage is applied to the array.
t
The erase operation is disabled.
MERASE
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is the mass erase time.
NVS
MERASE
Figure 3
.
.
shows mass erase and page erase
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AN2156