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GMS90C58 数据表(PDF) 53 Page - Hynix Semiconductor |
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GMS90C58 数据表(HTML) 53 Page - Hynix Semiconductor |
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53 / 59 page  GMS90 Series Oct. 2000 Ver 3.1a 49 Program Memory Lock Bits The two-level Program Lock system consists of 2 Lock bits and a 32-byte (64-byte for GMS97X54/ 56/58) Encryption Array which are used to protect the program memory against software piracy. Encryption Array: Within the EPROM array are 32 bytes (64 bytes for GMS97X54/56/58) of Encryption Array that are initially unprogrammed (all 1s). Every time that a byte is addressed during a verify, address lines are used to select a byte of the Encryption array. This byte is then exclusive-NORed (XNOR) with the code byte, creating an Encrypted Verify byte. The algorithm, with the array in the unprogrammed state (all 1s), will return the code in its original, unmodified form, It is recommended that whenever the Encryption Array is used, at least one of the Lock Bits be pro- grammed as well. Program / Verify algorithms Any algorithm in agreement with the conditions listed in Table 11, and which satisfies the timing specifications is suitable. Notes: 1. “0” = Valid low for that pin, "1" = valid high for that pin. 2. VPP =12.75V ± 0.25V 3. VCC =5V ± 10% during programming and verification. 4. ALE/PROG receives 25 (10 for GMS97X54/56/58) programming pulses while VPP is held at 12.75V. Each programming pulse is low for 100us ( ± 10us) and high for a minimum of 10µs. Table 11. EPROM programming modes MODE RST PSEN ALE/ PROG EA/ VPP P2.7 P2.6 P3.7 P3.6 Read Signature 10110 000 Program Code Data 100 VPP 1 011 Verify Code Data 10110 011 Program encryption table 100 VPP 1 010 Program security bit 1 100 VPP 1 111 Program security bit 2 100 VPP 1 100 Lock Bit Protection Modes U: unprogrammed, P: programmed Mode LB1 LB2 Protection Type 1 U U No program lock features 2 P U Further programming of the EPROM is disabled 3 P P Same as mode2, alsoverify is disabled |
类似零件编号 - GMS90C58 |
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类似说明 - GMS90C58 |
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