1. A method of enabling detection of tampering with data provided to a programmable integrated circuit, the method comprising:
generating a plurality of instructions, each instruction of the plurality of instructions having a plurality of fields for implementing the instruction, wherein a field of the plurality of fields may receive one of a plurality of encoded values for a particular instruction;
selecting an encoded value of the plurality of encoded values to be inserted in the field of an instruction to establish randomness in the instruction, wherein encoded values for two of the particular instruction in a row are selected to have different encoded values; and
inserting, by a computer, a redundancy check value in the instruction, wherein the redundancy check value is based upon the selected encoded value of the plurality of encoded values.
2. The method of claim 1 further comprising performing, by the programmable integrated circuit, error detection using the redundancy check value.
3. The method of claim 2 wherein performing error detection comprises performing error detection for each instruction of the plurality of instructions in the data.
4. The method of claim 2 wherein performing error detection comprises performing error detection in response to an instruction to perform a redundancy check inserted in the plurality of instructions in the data.
5. The method of claim 1 further comprising encrypting the data.
6. The method of claim 1, wherein the modifying unused bits of a field of the plurality of fields of an instruction comprises:
establishing multiple encoded values for the field of the instruction; and
generating, by a computer, a bitstream having the selected encoded value for configuring the programmable integrated circuit.
7. The method of claim 6 wherein selecting an encoded value of the plurality of encoded values comprises selecting the encoded value at random.
8. The method of claim 6 wherein establishing multiple encoded values for the field of the instruction comprises establishing multiple encoded values for an operational code of the instruction.
9. The method of claim 8 wherein establishing multiple encoded values for the field of the instruction comprises establishing multiple encoded values for a write instruction, wherein one encoded value of the multiple encoded values indicates that data associated with the write instruction is encoded.
10. The method of claim 6 wherein establishing multiple encoded values for the field of the instruction comprises allowing multiple addresses of an address field to map to a given register.
11. The method of claim 6 further comprising inserting an error code value in an error code field of the instruction, wherein the error code value is based upon the selected encoded value.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A process cartridge detachably mountable on a main body of an electrophotographic image forming apparatus, said process cartridge comprising:
(a) an electrophotographic photosensitive member;
(b) developing means having a developer container containing therein a developer for developing an electrostatic latent image formed on said electrophotographic photosensitive member; and
(c) planar developer amount measuring means having a pair of electrodes arranged at a predetermined interval in said developer container;
the pair of electrodes of said planar developer amount measuring means being constructed in different patterns in conformity with an initial fill developer amount in said developer container.
2. The process cartridge according to claim 1, wherein heights of said pair of electrodes in a direction in which the developer decreases differ from each other, and areas thereof are constant.
3. The process cartridge according to claim 1, wherein heights of and the interval between said pair of electrodes in a direction in which the developer decreases, and areas of widths of the electrodes differ.
4. An electrophotographic image forming apparatus for forming an image on a recording medium on which a process cartridge is detachably mountable, comprising:
(a) mounting means for detachably mounting the process cartridge, said process cartridge having:
an electrophotographic photosensitive member;
developing means having a developer container containing therein a developer for developing an electrostatic latent image formed on said electrophotographic photosensitive member; and
planar developer amount measuring means having a pair of electrodes arranged at a predetermined interval in said developer container; and
(b) developer amount indicating means for indicating an amount of developer in said developer container as a ratio to an initial fill developer amount;
the pair of electrodes of said planar developer amount measuring means being constructed in different patterns in conformity with the initial fill developer amount in said developer container.
5. The electrophotographic image forming apparatus according to claim 4, wherein heights of said pair of electrodes in a direction in which the developer decreases differ from each other, and areas thereof are constant.
6. The electrophotographic image forming apparatus according to claim 4, wherein heights of and the interval between said pair of electrodes in a direction in which the developer decreases, and areas of widths of the electrodes differ.