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Preliminary C8051F120/1/2/3 C8051F124/5/6/7 - KEMT FEI TUKE

Preliminary C8051F120/1/2/3 C8051F124/5/6/7 - KEMT FEI TUKE

Preliminary C8051F120/1/2/3 C8051F124/5/6/7 - KEMT FEI TUKE

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<strong>C8051F120</strong>/1/2/3<br />

<strong>C8051F124</strong>/5/6/7<br />

<strong>Preliminary</strong><br />

Table 15.1. FLASH Electrical Characteristics<br />

VDD = 2.7 to 3.6 V; -40°C to +85°C<br />

PARAMETER CONDITIONS MIN TYP MAX UNITS<br />

Endurance 20k 100k Erase/Write<br />

Erase Cycle Time 10 12 14 ms<br />

Write Cycle Time 40 50 60 µs<br />

15.2. Security Options<br />

The CIP-51 provides security options to protect the FLASH memory from inadvertent modification by software as<br />

well as prevent the viewing of proprietary program code and constants. The Program Store Write Enable (PSCTL.0),<br />

Program Store Erase Enable (PSCTL.1), and Flash Write/Erase Enable (FLACL.0) bits protect the FLASH memory<br />

from accidental modification by software. These bits must be explicitly set to logic 1 before software can write or<br />

erase the FLASH memory. Additional security features prevent proprietary program code and data constants from<br />

being read or altered across the JTAG interface or by software running on the system controller.<br />

A set of security lock bytes stored at 0x1FBFF and 0x1FBFE protect the FLASH program memory from being read<br />

or altered across the JTAG interface. Each bit in a security lock-byte protects one 16k-byte block of memory. Access<br />

to the scratchpad area can only be locked by locking all other FLASH blocks. Clearing a bit to logic 0 in a Read Lock<br />

Byte prevents the corresponding block of FLASH memory from being read across the JTAG interface. Clearing a bit<br />

in the Write/Erase Lock Byte protects the block from JTAG erasures and/or writes. The Read Lock Byte is at location<br />

0x1FBFF. The Write/Erase Lock Byte is located at 0x1FBFE. Figure 15.2 shows the location and bit definitions of<br />

the security bytes. The 1024-byte sector containing the lock bytes can be written to, but not erased by software. An<br />

attempted read of a read-locked byte returns undefined data. Debugging code in a read-locked sector is not possible<br />

through the JTAG interface. To ensure protection from external access, the block containing the lock bytes<br />

(1C000-1BFFF) must be write/erase locked by clearing the MSB of byte 0x1FBFE.<br />

Page 176<br />

DS008-0.8-AUG02 © 2002 Cygnal Integrated Products, Inc.

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