************************************************************************ ************************************************************************ ** ** ** Application notes for Ramtron devices ** ** ** ** (Informal Document) ** ** ** ** To find the application notes for your device search for the ** ** 'core' part name. As an example using the FM25L256 8 pin SOIC ** ** you would search this document for the entry "25L256" ** ** ** ************************************************************************ ************************************************************************ ************************************************************************ 24CL04 ---------- 25040 ---------- 25CL64 ---------- 25256 ---------- 25L256 ---------- 25640 ---------- There are four levels of Block Protection that can be supported on these devices: Start/End Block (BP1), (BP0) Protection Addresses Security Fuse settings: SF2, SF1 25040/24CL04 ------------------------------------ -------------------- 0, 0 None 0, 1 $0300->$03FF 1, 0 $0200->$03FF 1, 1 $0000->$03FF ---------------------------------------------------------------- Start/End Block (BP1), (BP0 Protection Addresses Security Fuse settings: SF2, SF1 25CL64 ------------------------------------ -------------------- 0, 0 None 0, 1 $1800->$1FFF 1, 0 $1000->$1FFF 1, 1 $0000->$1FFF ---------------------------------------------------------------- Start/End Block (BP1), (BP0) Protection Addresses Security Fuse settings: SF2, SF1 25256/25L256 ------------------------------------ -------------------- 0, 0 None 0, 1 $6000->$7FFF 1, 0 $4000->$7FFF 1, 1 $0000->$7FFF ---------------------------------------------------------------- Start/End Block (BP1), (BP0) Protection Addresses Security Fuse settings: SF2, SF1 25640 ------------------------------------ -------------------- 0, 0 None 0, 1 $1800->$1FFF 1, 0 $1000->$1FFF 1, 1 $0000->$1FFF ---------------------------------------------------------------- Enabling the "Erase EE device" option will ONLY remove all block protection. NOTE: The "Erase EE device" option must be enabled when re-programming the device in order to remove the Block Protection. NOTE: The "Erase EE device" option will NOT Erase the device. To re-program the device you must disable Blank/Illegal Bit checks flags. To program the Hardware Write Protection option (WPEN) enable the "Program protect reg." flag. Performing a Load operation will also load the Status Register Protection Bits into the following address locations in User RAM: 25CL64 = Address $2000 25640 = Address $2000 25256 = Address $8000 25L256 = Address $8000 The data format in the Programmer's User RAM will follow the same format as defined in the corresponding device's data sheet. Status Register Format in relation to the Protection Bits: ------------------------------------------------------- |Bit 7 |Bit 6 |Bit 5 |Bit 4 |Bit 3 |Bit 2 |Bit 1 |Bit 0 | |-------------------------------------------------------| | WPEN | X | X | X | BP1 | BP0 | X | X | ------------------------------------------------------- ***********************************************************************