PROGRAMMING THE NONVOLATILE MEMORY

Table 16-1. 87C196Mx OTPROM Memory Map

Address Range

Description

(Hex)

 

 

 

9FFF (MH)

Program memory

2080

 

5FFF (MC, MD)

Program memory

2080

 

207F

Reserved (each location must contain FFH)

205E

 

205D

PTS vectors

2040

 

203F

Upper interrupt vectors

2030

 

202F

Security key

2020

 

201F

Reserved (each location must contain FFH)

201C

 

201B

Reserved (must contain 20H)

201A

CCB1

2019

Reserved (must contain 20H)

2018

CCB0

2017

Reserved (each location must contain FFH)

2014

 

2013

Lower interrupt vectors

2000

 

16.3 SECURITY FEATURES

Several security features enable you to control access to both internal and external memory. Read and write protection bits in the chip configuration register (CCR0), combined with a security key, allow various levels of internal memory protection. Two UPROM bits disable fetches of instruc- tions and data from external memory. (See Figure 16-1 on page 16-7 for more information.)

16.3.1 Controlling Access to Internal Memory

The lock bits in the chip configuration register (CCR0) control access to the OTPROM. The reset sequence loads the CCRs from the CCBs for normal operation and from the PCCBs when enter- ing programming modes. You can program the CCBs using any of the programming methods, but only slave and PCCB programming modes allow you to program the PCCBs.

NOTE

The developers have made a substantial effort to provide an adequate program protection scheme. However, Intel cannot and does not guarantee that these protection methods will always prevent unauthorized access.

16-3

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Intel 8XC196MC, 8XC196MD, 8XC196MH manual Security Features, Controlling Access to Internal Memory, C196Mx Otprom Memory Map