MC68HC708AS48 FREESCALE [Freescale Semiconductor, Inc], MC68HC708AS48 Datasheet - Page 58

• Manufacturer Part Number: MC68HC708AS48
• Description: Advance Information
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Erasable Programmable Read-Only Memory
4.3 Functional Description
Advance Information
58
NOTE:
Erasable Programmable Read-Only Memory (EPROM/OTPROM)
The user EPROM/OTPROM consists of 49,152 bytes of user
EPROM/OTPROM from addresses $3E00-$FDFF and 36 bytes of user
interrupt and reset vector EPROM/OTPROM from addresses
$FFFC–$FFFF. See
Security has been incorporated into the MC68HC708AS48 to prevent
external viewing of the EPROM/OTPROM contents. This feature
ensures that customer-developed software remains proprietary.
The MC68HC708AS48 with a quartz window (engineering samples
only) has 49,152 user bytes and 36 vector bytes of erasable,
programmable ROM (EPROM). The quartz window allows EPROM
erasure by exposure to ultraviolet light. In the MC68HC708AS48CFN,
without the quartz window, the EPROM cannot be erased and serves as
49,152 user bytes and 36 vector bytes of one-time programmable ROM
(OTPROM). An unprogrammed or erased location reads as $00. The
following addresses are user EPROM/OTPROM locations:
Programming tools are available from Motorola. Contact your local
Motorola representative for more information.
1. No security feature is absolutely secure. However, Motorola’s strategy is to make reading or
copying the EPROM/OTPROM difficult for unauthorized users.
•
•
$3E00–$FDFF
$FFDC–$FFFF (These locations are reserved for user-defined
interrupt and reset vectors.)
Figure 2-1. Memory
Map.
MC68HC708AS48
MOTOROLA
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1
Rev. 4.0