JPS61248298A - Prom circuit - Google Patents

Abstract

PURPOSE:To attain all kinds of writing methods by connecting all signal lines and power supply lines between PROM circuits and its reading circuit through connectors, and in case of PROM writing, separating the PROM circuit simply from its reading circuit. CONSTITUTION:In case of reading out the contents of the PROMs 1a, 1b, connector pins 12, 15 are connected with each other by a short connector 16 to read out the contents. In case of writing data in the PROMs 1a, 1b, the connector pin 15 is separated from the short connector 16 and a PROM writing connector 20 is connected to the connector pin 15 to write the data in the PROMs. Since the PROMs are separated from the reading circuit 9 in case of writing, any influence will not be exerted upon the reading circuit 9. Thus, data can be simply written on any kinds of PROMs.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a PROM circuit (programmable read-only memory circuit), and particularly to writing thereof.

[Conventional technology]

Figure 2 shows, for example, Intel's manual 1sBc.
86/14/30 Single Board Com
puter f(ardwareReference
Conventional PROM that simplifies 3heet 2 and 5heet 5 etc. from Manual (published in 1982)
It is a block diagram of a circuit. In the figure (la), (lb
) ti each represents a PROM, (address) in the figure is an address bus input terminal, (data) is a data bus input terminal, CE is a chip select signal input terminal, and 2 is a program signal input terminal. (2a), ( 2b) are ICs that connect PROMs (la) and (lb), respectively.
Socket, (3) is PROM (la), (lb)
The data bus 141 of PROM (la), (lb)
Address bus (5) to PROM (la), (l
(6) is the address decoder for generating the chip select signal, (7) is the F
Program signals for ROM (la) and (lb), (8) is the CPU.

In the example shown in Fig. 2, reading of PROMs (la) and (lb) is not done from CPU (8), but from PR
Writing to OM (la), (lb) is also done by the CPU (8
), therefore the CPU (8) is performed from the PROM (
la), (lb), data signal, address signal, chip select signal (5), program signal (7)
) is output.

Reading from PROMs (la) and (lb) is generally well known, so in the device shown in FIG.
The operation when writing to OM (la) and (lb) will be described below.

When writing data to an address location in either PROM (la) or (lb), the CPU T8) outputs an address signal indicating the address location onto the address bus (4). The upper bit of this address signal is subcoded by the address decoder (6) and becomes a chip select signal (5), which selects either PROM (la) or (lb). The address signal excluding the upper bits input to (6) is input in parallel to PROMs (la) and (lb), and the address signal input to PROM (la) and (lb) is input to
It is held by a latch (not shown) in the ROM.

Next, CPUt81 outputs a program signal (7),
Output data on the data bus (3). The data bus (5) is placed at the address position determined by the address signal in the PROM selected by the chip select signal (5).
The above data will be written.

In addition, as another writing method, the FR to be written
OM″Ik Pull it out from the IC socket and then PRO
There is also a method of writing by connecting to an M writing device.

[Problem that the invention seeks to solve]

The conventional PROM circuit is configured as described above, so when writing from the CPU (8), the PROM is left in the same connection state as when reading, and the comparison necessary for writing is performed. Since a large amount of electric power must be applied, there is a risk of destroying peripheral elements, and in order to avoid accidents such as destruction of peripheral elements, various restrictions must be placed on the writing method. There was a point.

Furthermore, the method of removing the PROM from the IC socket for writing has had problems such as incorrect insertion or poor contact with the IC socket.

The present invention was made to solve the above-mentioned problems, and aims to provide a FROM circuit that can use all kinds of writing methods for PROM.

[Means for solving problems]

In this invention, all signal lines and power supply lines between a PROM circuit and its readout circuit are connected through connectors, so that the PROM circuit can be easily separated from its readout circuit in the case of PROM writing.

[Effect]

In the case of PROM writing, since writing is performed after separating the PROM circuit from its reading circuit, all kinds of writing methods are possible.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.
In the figure, (la) and (lb) indicate the same or corresponding parts as the same reference numerals in Fig. 2, and (9) indicates the PROM (l
a).

(1b) is a readout circuit that performs readout, (10) is a signal line from the readout circuit, and the data bus (3) of the circuit in FIG.
Contains signals corresponding to address bus (4) and chip select signal line (5), (11) is PROM (la), (
(12) is the connector pin on the readout circuit side to which the signal line (10) and power line (11) are connected;
(13) corresponds to the signal line (10) and PROM (la
), (lb) are connected to the signal line, (14) is the power supply line (
11) and the power line connected to PROM (la) and (lb), (15) is the signal line (13) and power line (14).
) is connected to the connector pin on the PROM side, (16) is a short-circuit connector that connects the connector pin (12) on the readout circuit side and the connector pin (15) on the PROM side, (17)
is a PROM writing and programming device (18) that writes to PROM.
) is the PROM output from the PROM writing device (17)
Write signal line, (19) is PROM write power supply line output from PROM writing device (17), (20) is PRO
M write signal line (18), PROM write power supply line (19)
) is the PROM write connector to which it is connected.

When reading PROMs (la) and (lb), the connector bins (12) and (15) are connected by a shorting connector (16), and reading is performed.

When writing to PROM (la), (lb), disconnect from the connector bin (15) e short-circuit connector (16), connect the PROM write connector (20) to the connector bin (15), and write to the PROM. Write.

In this case, since the PROM is separated from the readout circuit (9), writing to the PROM does not affect the subsequent readout circuit (9).

In the above embodiment, the connector bins (12) and (15) are connected by the short-circuit connector (16) during normal reading, but this connection may be made by any other method. 15) may be connected to the connector bin (12) via an easily attachable/detachable connecting device.

Moreover, any type of connector may be used as long as it has a similar function.

〔Effect of the invention〕

As described above, according to the present invention, the PROM is configured so that it can be electrically separated from the readout circuit by detaching the connector, and writing to the PROM is performed in a separated state. It is possible to easily write to any type of PROM without adversely affecting the PROM, and there is no need to add complex circuitry to the PROM card for writing, making it easier for the device to operate. This has the effect of reducing cost.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
The figure is a block diagram of a conventional PROM circuit. (la) and (lb) are PROM and (10
) is the signal line on the readout circuit side, (11) tel: power supply line on the readout circuit side, (12) is the connector pin on the readout circuit side, (1
3) is the signal line on the PROM side, (14) is the power line on the PROM side, (15) is the connector pin on the PROM side, (16)
is the short-circuit connector, (17) is the PROM writing device, and (18) is the short-circuit connector.
)fiPROM'! Included signal line, (19) is PROM
The write power supply line (20) is a PROM write connector. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (3)

[Claims] (1) From the reading circuit that reads the PROM circuit (programmable read-only memory circuit) to the PRO
Respective pins of the first connector to which signal lines including address signal lines and data signal lines up to M and power supply lines are respectively connected, and the signal lines and power supply lines connected to the PROM are respectively connected. Each pin of a second connector, a PRO equipped with an easily attachable/detachable connecting device that connects between corresponding pins of the first connector and the second connector.
M circuit. (2) The easily attachable/detachable connecting device includes a short-circuit connector that connects each pin of the first connector and each pin of the second connector. PROM circuit as described. (3) Each pin of the second connector is connected to the signal line and power line from the PROM writing device when the connection between the second connector and the connecting device is disconnected, and writes to the PROM. A PROM circuit according to claim 1, characterized in that it can perform