JPH0764952A - Microprogram control unit with built-in flash memory - Google Patents

Abstract

PURPOSE:To reload the contents of a flash memory after mounting an MCU with the built-in flash memory by utilizing an internal circuit mounted on the same substrate without using an exterior circuit and an exclusive jig. CONSTITUTION:After setting a write mode to the flash memory 1, the reloading data of the flash memory 1 are supplied from an external bus 9 through a serial I/O signal line 10 to a serial I/O circuit 4 mounted on the same substrate S, the reloading data supplied to the serial I/O circuit 4 are successively written in the write address of the flash memory 1 automatically generated by a latch and write control circuit 11 with an automatic address generation function and the contents of the entire area of the flash memory 1 are reloaded.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a flash memory, CP
It relates to a micro program control unit (hereinafter referred to as an MCU) in which a U and a bus interface circuit are mounted on the same board. More specifically, it relates to a function for rewriting the contents of the flash memory in the mounted flash memory MCU.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing a content rewriting mechanism of a conventional MCU with a built-in flash memory, which rewrites the content of a flash memory in a mounted state using an external circuit. In the figure, 1 is a rewritable flash memory, 2 is a CPU, 3 is an input / output port circuit for inputting / outputting data to / from an internal device of a system using a flash memory built-in MCU, 6 is a flash memory 1 A write control signal line for giving a write control signal for permitting / prohibiting the write of to the flash memory 1 or the like to set a write / read mode for the flash memory 1,
13 is an internal bus of the MCU with built-in flash memory, 15 is a write control circuit for controlling the write timing to the flash memory 1, flash memory 1, CPU
2, the input / output port circuit 3, the write control signal line 6, the internal bus 13, and the write control circuit 15 are mounted on the same substrate S.

Further, in the figure, 9 is a built-in flash memory
An external bus running in the system using the MCU, 16 selects either a port signal from the outside of the MCU or an address / data signal for rewriting the flash memory 1 as a signal to be sent to the input / output port circuit 3 depending on the state of the write control signal. Then, connect the I / O port circuit 3 to the port signal lines 7 and 8.
Alternatively, it is a port connection signal switching circuit for switching to the address input signal line 17 / data input signal line 18.

Next, the operation of rewriting the contents of the flash memory in the conventional example 1 having the configuration shown in FIG. 5 will be described. First, the flash memory 1, the input / output port circuit 3, and the write control circuit are set by setting the write control signal 6 for permitting / prohibiting the writing to the flash memory 1 inside the MCU mounted on the substrate S to the write permission level. 15. Set the port connection signal switching circuit 16 to the write mode.

When the port connection signal switching circuit 16 enters the write mode, the address input signal line is externally supplied.
An address signal given via 17 is taken into the write control circuit 15 from the input / output port circuit 3, and
A data signal given from the outside through the data input signal line 18 is taken into the write control circuit 15 from the input / output port circuit 3. The address signal and the data signal taken into the write control circuit 15 are sent to the flash memory 1 at respective input timings controlled by the write control circuit 15, and a new data signal is added to the address of the flash memory 1 indicated by the address signal. Is written.

FIG. 6 is a diagram showing a content rewriting mechanism of another conventional MCU with a built-in flash memory that rewrites the content of the flash memory in a mounted state using a probe-type writing jig. Incidentally, the same or corresponding parts as those of the above-mentioned conventional example are designated by the same reference numerals, and the description thereof will be omitted. In this conventional example, instead of the port connection signal switching circuit 16 in the previous conventional example, a probe contact 19 for externally applying a probe to the substrate S for rewriting the contents of the flash memory 1 and a signal used in the probe. A protective resistor 20 of is provided.

Next, the operation of rewriting the contents of the flash memory in the conventional example 2 having the configuration shown in FIG. 6 will be described. First, the writing / writing to the flash memory 1 inside the MCU mounted on the board S from the probe applied to the probe terminal 19 on the board S for rewriting the internal flash memory from the outside on the board S is permitted / prohibited. By setting the write control signal 6 to the write permission level, the flash memory 1, the input / output port circuit 3, and the write control circuit 15 are set to the write mode. At this time, the external signal supplied from the probe becomes effective for the flash memory built-in MCU on the substrate S by providing the protection resistor 10.

Next, the write address signal to the flash memory 1 input by applying the probe to the probe terminal 19 is transmitted from the input / output port circuit 3 to the write control circuit 15, and the probe is applied to the probe terminal 19 as well. The write data signal to the flash memory 1 inputted as described above is also taken into the write control circuit 15 from the input / output port circuit 3. The address signal and the data signal taken into the write control circuit 15 are sent to the flash memory 1 at respective input timings controlled by the write control circuit 15, and a new data signal is added to the address of the flash memory 1 indicated by the address signal. Is written.

[0009]

The conventional MCU with a built-in flash memory requires an external circuit and a contact for a dedicated rewriting jig to rewrite the flash memory once mounted on the board. There is a problem that the system scale becomes large when using the MCU.

The present invention has been made to solve such a problem, and is provided with a function of rewriting the contents of a flash memory by utilizing an internal circuit mounted on the same substrate of a flash memory built-in MCU. By
MCU with built-in flash memory that keeps system size small
For the purpose of providing.

[0011]

An MCU with a built-in flash memory according to a first aspect of the present invention is an external bus such as a bus interface circuit and a serial I / O circuit mounted on the same substrate as a mounted MCU with a built-in flash memory. It is characterized in that a write control circuit for automatically generating a write address to the flash memory and rewriting the entire contents of the flash memory is provided by using an interface circuit between and.

MC with built-in flash memory according to the second invention
U is added to the rewrite data of the flash memory by using the interface circuit between the built-in flash memory built-in MCU and the external bus such as the bus interface circuit and serial I / O circuit mounted on the same board. A write control circuit for writing rewrite data to a write address of the flash memory is provided.

[0013]

Operation: MCU with built-in flash memory according to the first invention
Provides the flash memory rewrite data to the bus interface circuit mounted on the same substrate as the MCU with built-in flash memory, the interface circuit with the external bus such as the serial I / O circuit, and the write control circuit automatically generates the address. Rewriting data is sequentially written to the flash memory at this address, and the contents of the flash memory are rewritten.

MC with built-in flash memory according to the second invention
U gives the data added with the write address of the flash memory rewrite data to the rewrite data to the bus interface circuit mounted on the same board as the MCU with built-in flash memory and the interface circuit with the external bus such as the serial I / O circuit. The write control circuit writes the rewrite data to the write address of the flash memory included in this data, and rewrites the content of the flash memory.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments. Example 1. FIG. 1 shows an MC with a built-in flash memory according to the present invention.
It is a block diagram which shows the structure of U. In the figure, 1 is a rewritable flash memory, 2 is a CPU, 3 is an input / output port circuit for inputting / outputting data from / to other devices of a system using a flash memory built-in MCU, and 4 is a system internal circuit. Serial I / O signal line 10 to / from external bus 9
Latch / write control circuit with automatic address generation function which will be described later by serially inputting / outputting data through the rewriting data of the flash memory 1 input from the external bus 9.
A serial I / O circuit to be given to 11, and a flash memory 1 is given a write control signal from an MPU or the like (not shown) that controls the entire system in order to enable / disable writing to the flash memory 1. A write control signal line that sets the write / read mode for 1; 13 is the internal bus of the MCU with built-in flash memory; 11 is the address for automatically writing to the flash memory 1 and the data given from the serial I / O circuit 4. Is a latch / write control circuit with an automatic address generation function for latching the data, controlling the write timing, and writing the data in the flash memory 1.

Flash memory 1, CPU 2, input / output port circuit 3, serial I / O circuit 4, write control signal line 6, serial I / O signal line 10, latch / write control circuit 11 with automatic address generation function, internal The buses 13 are mounted on the same substrate S. Further, in the figure, 7 and 8 are port signal lines for inputting / outputting external signals to / from the input / output port circuit 3.

Next, the operation of the first embodiment will be described. First, the flash memory 1 inside the MCU mounted on the board S
Is set to the write / read state. By setting the write control signal 6 to the write state, the flash memory 1, the input / output port circuit 3, the serial I / O circuit 4, and the latch / write control circuit 11 with the automatic address generation function are set. Enter write mode.

As a result, the serial I / O circuit 4 receives the rewrite data signal of the flash memory 1 serially transferred from the external bus 9 and sends it to the latch / write control circuit 11 with the automatic address generating function. The latch / write control circuit 11 with the automatic address generation function automatically generates and latches the write address to the flash memory 1, and also latches the data from the serial I / O circuit 4 and outputs the address and the data at each output timing. In response to this, the data is sent to the flash memory 1, and the rewriting data is sequentially written in the entire area from the first address to the last address of the flash memory 1 which is automatically generated.

Example 2. FIG. 2 is a block diagram showing the configuration of the second embodiment of the MCU with a built-in flash memory according to the present invention. The same or corresponding parts as those of the first embodiment are designated by the same reference numerals and their description is omitted. In this embodiment, serial I / O
The rewriting data of the flash memory 1 serially input from the external bus 9 through the signal line 10 is added with the write address of the rewriting data to the flash memory 1 and supplied to the serial I / O circuit 4. Example 1
Instead of the latch / write control circuit 11 with the automatic address generation function, the rewrite data including the write address from the serial I / O circuit 4 is latched, and the rewrite data is output to this write address of the flash memory 1 at its output timing. A latch / write control circuit 12 for writing in response is provided.

Next, the operation of the second embodiment will be described.
First, the flash memory 1, the I / O port circuit 3, the serial I / O circuit is set by setting the write control signal 6 that sets the flash memory 1 inside the MCU mounted on the board S to the write / read state. 4,
The latch / write control circuit 12 is set to the write mode.

As a result, the serial I / O circuit 4 receives the rewriting data to the flash memory 1 serially transferred from the external bus 9 and the rewriting data signal including the write address, and the latch / write control circuit receives the rewriting data signal.
Send to 12. The latch / write control circuit 12 uses the first 2 bytes of the rewrite data signal as the write address,
The next 1 byte is used as rewrite data, each signal is latched at each fetch timing, sent to the flash memory 1 according to each output timing, and the rewrite data is written to the address of the flash memory 1 designated by the write address. Written.

Example 3. FIG. 3 is a block diagram showing the configuration of a third embodiment of an MCU with a built-in flash memory according to the present invention. The same or corresponding parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, instead of the serial I / O circuit 4 of the first embodiment, the bus interface circuit 5 is used for rewriting the contents of the flash memory 1, and the rewriting data of the flash memory 1 is transferred from the external bus 9. It is input to the bus interface circuit 5 via the bus interface signal line 14.

Next, the operation of the third embodiment will be described.
First, by setting the write control signal 6 for setting the flash memory 1 inside the MCU mounted on the board S to the write / read state, the flash memory 1, the input / output port circuit 3, the bus interface circuit 5, The latch / write control circuit 11 with the automatic address generation function is set to the write mode.

As a result, the bus interface circuit 5
Receives the rewrite data signal of the flash memory 1 sequentially transferred from the external bus 9 and sends it to the latch / write control circuit 11 with the automatic address generating function. The latch / write control circuit 11 with an automatic address generation function automatically generates and latches a write address to the flash memory 1 and latches the data from the bus interface circuit 5 according to the output timing of each address and data. The rewriting data is sent to the flash memory 1 and the rewriting data is sequentially written in the entire area from the first address to the last address of the flash memory 1 which is automatically generated.

Example 4. FIG. 4 is a block diagram showing the configuration of a fourth embodiment of an MCU with a built-in flash memory according to the present invention. The same or corresponding parts as those of the third embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the rewrite data of the flash memory 1 input from the external bus 9 via the bus interface signal line 14 is used as the flash memory 1
It is configured to add a write address of rewrite data to the bus interface circuit 5 and supply it to the bus interface circuit 5 instead of the latch / write control circuit 11 with the automatic address generation function in the third embodiment.
A latch / write control circuit 12 is provided for latching rewrite data including a write address from, and writing the rewrite data at this write address of the flash memory 1 in accordance with its output timing.

Next, the operation of the fourth embodiment will be described.
First, by setting the write control signal 6 for setting the flash memory 1 inside the MCU mounted on the board S to the write / read state, the flash memory 1, the input / output port circuit 3, the bus interface circuit 5, The latch / write control circuit 12 is set to the write mode.

As a result, the bus interface circuit 5
Is a latch / write control circuit which receives the rewrite data to the flash memory 1 sequentially transferred from the external bus 9 and the rewrite data signal including the write address.
Send to 12. The latch / write control circuit 12 uses the first 2 bytes of the rewrite data signal as the write address,
The next 1 byte is used as rewrite data, each signal is latched at each fetch timing, sent to the flash memory 1 according to each output timing, and the rewrite data is written to the address of the flash memory 1 designated by the write address. Written.

[0028]

As described above, since the MCU with a built-in flash memory according to the present invention rewrites the contents of the mounted flash memory by using the internal circuit mounted on the same substrate, the inner part of the flash memory can be rewritten. It is possible to rewrite the contents in the mounted state without the need for an external circuit and a contact for a rewriting jig.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of an MCU with a built-in flash memory according to the present invention.

FIG. 2 is a block diagram showing a configuration of a second embodiment of an MCU with a built-in flash memory according to the present invention.

FIG. 3 is a block diagram showing the configuration of a third embodiment of the MCU with a built-in flash memory according to the present invention.

FIG. 4 is a block diagram showing a configuration of a fourth embodiment of the MCU with a built-in flash memory according to the present invention.

FIG. 5 is a block diagram of a conventional MCU with a built-in flash memory that rewrites the contents of the flash memory using an external circuit.

FIG. 6 is a block diagram of a conventional MCU with a built-in flash memory that rewrites the contents of the flash memory using a rewriting probe.

[Explanation of symbols]

1 Flash memory 2 CPU 3 I / O port circuit 4 Serial I / O circuit 5 Bus interface circuit 6 Write control signal line 9 External bus 10 Serial I / O signal line 11 Latch / write control circuit with automatic address generation function 12 Latch / write Control circuit 14 Bus interface signal line S board

Claims (2)

[Claims] 1. A microprogram control unit with a built-in flash memory mounted on a board, and means for supplying rewriting data of the flash memory to an interface circuit mounted on the board and controlling data input / output with an external bus. And a write control circuit which is mounted on the substrate, automatically generates a write address to the flash memory, and sequentially writes the rewrite data given to the interface circuit to the write address. Micro program control unit with built-in flash memory. 2. A flash memory built-in micro program control unit mounted on a board, wherein data in which a write address of the rewrite data is added to rewrite data of the flash memory is mounted on the board,
Means for providing an interface circuit for controlling data input / output with an external bus, and mounted on the board,
A microprogram control unit with a built-in flash memory, comprising a write control circuit for writing the rewrite data at a write address added to the data given to the interface circuit.