Reprogramming Device of a Flash Memory

This application makes claims all benefits accruing under 35 U.S.C. .sctn.119 from an application for REPROGRAMMING DEVICE OF A FLASH MEMORY earlier filed in the Korean Industrial Property Office on Dec. 5, 1995 and there duly assigned Ser. No. 46780/1995.

1. Field of the Invention

The present invention relates to a reprogramming device of a flash memory. More particularly, the present invention relates to a reprogramming device of a flash memory which makes the damaged flash memory usable again by reprogramming the flash memory.

2. Description of the Related Art

As is well-known, an effective memory and an effective memory handling is neccessary for an effective computer system. Among memories of a computer system, some situations involving memories (such as those involving flash memories) may require operations such as reprogramming, refresh, etc. before being usable again. An exemplar, of a contemporary practice in the related arts, is Tsuha (U.S. Pat. No. 5,511,176, Microcomputer Capable Of Accessing To An External Memory With Least Possible Wait, Apr. 23, 1996) disclosing a microcomputer capable of accessing to an external memory with least possible wait. In a refresh pulse producing circuit of a microcomputer, an access detection section detects access to a non-refresh memory area of an external memory to produce a non-refresh memory signal indicative of the access. Cartman et al. (U.S. Pat. No. 5,479,640, Memory Access System Including A Memory Controller With Memory Redrive Circuitry, Dec. 26, 1995) discloses a memory access for improving memory access when addressing dynamic random access modules (DRAMs). The memory access system includes a main memory and a memory controller. The main memory hardware redrives the last row address to the DRAMs after the completion of an access, so that the memory controller need not provide a row address to the memory for each command of a command sequence. Wada (U.S. Pat. No. 5,475,645, Memory Module Using DRAM And Method Of Refreshing The Memory Module, Dec. 12, 1995) discloses a memory module using a large capacity DRAM without a self-refresh mode, which maintains the contents of the memory irrespective of non-input of a refresh signal from a computer. Vrba (U.S. Pat. No. 5,473,770, Fault-Tolerant Computer System With Hidden Local Memory Refresh, Dec. 5, 1995) discloses a fault tolerant computer system having a plurality of processor modules having independent clocks for processing an instruction stream, global memory accessible by all of the processor modules, and a local memory configured within each processor modules and clocked synchronously therewith. The local memory is periodically refreshed or the refresh is aborted depending upon the number of clock cycles available before a local memory access occurs. Garinger et al. (U.S. Pat. No. 5,465,339, Decoupled Refresh On Local And System Busses In A PC/AT Or Similar Microprocessor Environment, Nov. 7, 1995) disclose a decoupled refresh on local and system busses in a PC/AT or similar microprocessor environment. Sugimoto (U.S. Pat. No. 5,440,711, Method For Controlling DRAM Memory In A Microcomputer, Aug. 8, 1995) discloses a microcomputer capable of elimination of the need of an external circuit and hence timing adjustment of the same, and of direct connection thereof to a memory. The DRAM controller includes a refresh controller for refreshing a DRAM. My study of the prior art and of the contemporary practice indicates a need for an effective reprogramming device of a flash memory which makes the damaged flash memory usable again by reprogramming the flash memory.

Accordingly, an object of the present invention is to provide an improved reprogramming device of a flash memory.

Another object of the present invention is to provide an improved reprogramming device of a flash memory which makes the damaged flash memory usable again by reprogramming the flash memory.

Another object of the present invention is to provide a reprogramming device that reprograms a flash memory under the condition that the flash memory is mounted in the main board.

Another object of the present invention is to provide a reprogramming device that reprograms a flash memory when a flash memory can not boot a computer system because the contents of a Basic Input Output System (BIOS), related to a basic operation of a computer system, are damaged in the flash memory.

Another object of the present invention is to provide a reprogramming device of a flash memory which can make the damaged flash memory usable again by reprogramming the flash memory which can not boot because of damage of the contents of the BIOS related to a basic operation of a computer system, under the condition of the flash memory being mounted in a main board.

To achieve one or more of these objects, a reprogramming device of a flash memory includes: a flash memory which stores BIOS data for a computer system; a central process unit which outputs an address signal after reading the BIOS data from the flash memory; random access memory which stores new BIOS data; and a controller driven by the address signal of the central process unit, which writes the new BIOS data of the random access memory on the flash memory. The device also includes a switch means which controls an operation of the flash memory; and reprogramming means which makes it possible to reprogram the flash memory under the condition that the flash memory is mounted in a main board when the flash memory can not boot the computer system because of damaged BIOS data.

To achieve these objects, the reprogramming device of a flash memory can use the steps of: disabling the flash memory; enabling the reprogramming means in order to reprogram the flash memory; and supplying power to the system for reprogramming. In addition, the steps can use the steps of initializing the system by reading the data from the reprogramming means; copying to the RAM a new BIOS data read from the reprogramming means; disabling the reprogramming means; enabling the flash memory for reprogramming; and reprogramming the flash memory after reading the BIOS data and turning off the system power.

A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein:

In the drawings:

FIG. 1 is a block diagram illustrating a structure of a reprogramming device of a flash memory according to a contemporary practice;

FIG. 2 is a block diagram illustrating a structure of a reprogramming device of a flash memory built in accordance with the principles of a preferred embodiment of the present invention; and

FIG. 3 is a flow chart for reprogramming a flash memory built in accordance with the principles of a preferred embodiment of the present invention.

Turning now to the drawings, FIG. 1 shows a reprogramming device of a flash memory according to a contemporary practice. This reprogramming device of a flash memory includes a flash memory 10 which stores BIOS data for a computer system, and a central process unit 20 which outputs an address signal after reading the BIOS data from the flash memory 10, a controller which performs read/write operation on the flash memory 10 by the address signal from the central process unit 20. The reprogramming device also includes a floppy disk drive 40 for reading the data recorded on a floppy disk or writing data on a floppy disk, a floppy disk controller 50 which outputs a control signal for operating the floppy disk drive 40, and a RAM 60 which stores the BIOS data of the flash memory 10 by the controller 30 and the floppy disk controller 50.

The operation of a reprogramming device of a flash memory, which has the above-mentioned structure, is as follows. In the situation of reading the BIOS data in the flash memory 10, the central process device 20 enables the controller by outputting an address signal when power is supplied to a computer system. The enabled controller 30, by the central process device 20, reads the BIOS data stored in the flash memory 10 through the data bus SD›7:0! by activating a ROM selection signal ROMCS#, a signal for reading a data MEMR# and an address signal SA›19:0! of the flash memory 10. Also, the controller 30 delivers the BIOS data read through the data bus SD›7:0! to the central process device 20 through a data bus D›31:0!.

In the situation of altering the BIOS data first recorded on the flash memory 10, the floppy disk is inserted. This stores a new BIOS data into the floppy disk drive 40. The floppy disk drive 40 reads the BIOS data on the floppy disk, when being driven by the floppy disk controller 50 which outputs a control signal after receiving a command from the central process device 20. The BIOS data read by the floppy disk drive, is inputted into the controller 30 through the data bus SD›7:0! and the controller 30 stores the BIOS data on the RAM 60. At this step, the controller 30 removes the BIOS data stored on the flash memory 10 and then reprograms the flash memory 10 by activating the address signal SA›19:0! of the flash memory 10, the signal for writing a data MEMW and the ROM selection signal ROMCS#, after reading a new BIOS data stored on the RAM 60 through the data bus SD›7:0!.

If the flash memory 10 is removed or the power is turned off at this programming step, the contents of the flash memory 10 are damaged. Accordingly, the system can not be booted and the flash memory 10 must be replaced. Also, such a reprogramming device of a flash memory of a contemporary practice has a disadvantage in that it is difficult to replace the flash memory because the flash memory is brazed on the main board.

As shown in FIG. 2, the reprogramming device of a flash memory in accordance with the purpose of the invention includes a flash memory 10 which stores BIOS data for a computer system, a central process unit 20 which outputs an address signal after reading the BIOS data from the flash memory, a random access memory 60 which stores new BIOS data, and a controller 30 driven by the address signal of the central process unit, which writes the new BIOS data of the random access memory on the flash memory. In addition, the device may include a switch 70 which controls an operation of the flash memory; and a reprogrammer 80 which makes it possible to reprogram the flash memory under the condition that the flash memory is mounted in a main board and that the flash memory can not boot the computer system because of damaged BIOS data.

The switch 70 includes a terminal Vcc and a pull-up resistor serially connected with a chip selection terminal of the flash memory 10, and a first switch SW1 whose one terminal is connected with a ROM selection signal ROMCS# and the other terminal is connected with the terminal Vcc and the pull-up resistor. The ROM selection signal ROMCS# is outputted from the controller 30 and the terminal Vcc and the pull-up resistor R1 turns on/off the flash memory chip.

The reprogrammer 80 includes a first ROM 81 which stores the data for operating or initializing or testing a computer system, a second ROM 82 which stores a new BIOS data, an address decoder 83 enabling a first ROM 81 and a second ROM 82 by decoding the signal outputted from the controller 30 and a second switch SW2 whose one terminal is connected with the address decoder 83 and another terminal is grounded. The second switch SW2 turns on/off the ROM chip selection signal ROMCS1#, ROMCS2# outputted from the address decoder 83.

The operation of the reprogramming device of a flash memory according to a preferred embodiment of the present invention, can be as follows. The user turns off the first switch SW1 of the switch 70, makes the flash memory 10 disable, and makes the reprogrammer 80 enable after turning on the second switch SW2. The central process device 20 enables the controller 30 when power is supplied to a computer system, and the controller 30 outputs an address signal for initializing a computer system through an address bus SA›19:0!. The address decoder 83, which receives an address signal outputted from the controller 30 as an input, initializes and tests a system after reading data from a first ROM 81 by activating a first ROM selection signal ROMSC1#.

At this step, if the controller 30 outputs an address signal SA›19:0! for writing a new BIOS data on the flash memory 10, the address decoder 83 reads a new BIOS data from the second ROM 82 by decoding the address signal SA›19:0! and activating the second ROM selection signal ROMCS2#, and stores the data on the RAM 60 in the system. At this step, the first switch SW1 is off although power is supplied. Accordingly, in order that a programming operation is not interrupted by the reprogrammer 80 during programming the flash memory 10 with a new BIOS data, the flash memory 10 must be enabled by turning on the first switch SW1 and the first ROM selection signal ROMCS1# and the second ROM selection signal ROMCS2# must be disabled by turning off the second switch SW2. The first ROM selection signal ROMCS1# is an output signal of the address decoder 83 of the reprogrammer 80. At this step, the flash memory 10 must read a new BIOS data from the RAM 60 in order to be reprogrammed. By turning off power and removing the external reprogrammer 80, all the work is finished and if power is supplied again, the central process device 20 performs normal operation by reading the BIOS data from the flash memory reprogrammed with a new BIOS data.

Therefore, the present invention which operates as above has an effect that a system board need not to be modified. Such operation as above permits a reprogramming of the flash memory under the condition that the flash memory is mounted in the main board. The programming can occur when the contents of a basic Input/Output System, related to a basic operation of a computer system, are damaged, lost, or even missing in the flash memory.

Thus, as mentioned in the previous paragraphs, the present invention can concern a reprogramming device of a flash memory, which includes a flash memory which stores basic input/output system data for a computer system, a central process unit which outputs an address signal after reading the basic input/output system data from the flash memory, a random access memory which stores new basic input/output system data, and a controller driven by the address signal of the central process unit. This writes the new basic input/output system data of the random access memory on the flash memory. The reprogramming device also includes a switch mechanism which controls an operation of the flash memory; and a reprogramming mechanism (or a reprogrammer) which makes it possible to reprogram the flash memory under the condition that the flash memory is mounted in a main board when the flash memory can not boot the computer system because of damaged basic input/output system data. The switch mechanism can include a pull-up terminal serially connected with a chip selection terminal of the flash memory, and a first switch whose one terminal is connected with a read only memory selection signal line and another terminal is connected with the pull-up terminal. The reprogramming mechanism can include a first read only memory which stores data for operating or initializing or testing a computer system, a second read only memory which stores the new basic input/output system data, an address decoder enabling the first read only memory and the second read only memory by decoding a signal outputted from the controller; and a second switch which turns on/off a first and a second read only memory chip selection signal outputted from the address decoder. A reprogramming method of the flash memory includes the steps of disabling a flash memory, enabling reprogramming means in order to reprogram the flash memory, and supplying power to a system for reprogramming. The method can include further steps of initializing the system by reading the data from the reprogramming means, copying to the random access memory a new basic input/output system data read from the reprogramming means, disabling the reprogramming means, enabling the flash memory for reprogramming, and reprogramming the flash memory after reading the basic input/output system data, and turning off a system power.