JPH0573698A - Microcomputer - Google Patents

Abstract

PURPOSE:To shorten the calculating time of average value data by calculating average value data of an AD conversion data with an AD converter incorporated in a microcomputer with a hardware incorporated in the microcomputer. CONSTITUTION:The system is provided with the AD converter 1, an adder 2 adding AD conversion data, a counter 3 counting the number of adding times, a register 5 setting the N value of an N times average value, a comparator 4 comparating the value of the counter 3 with the register 5 to output an signal, a selector 6 selecting average data from the adder 2, a latching circuit 7 latching the output signal of the selector 6, and a control part 8 controlling the AD converter 1, the adder 2 and the counter 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcomputer, and more particularly to an A / D having an input data average value calculation mechanism.
The present invention relates to a microcomputer including a converter.

[0002]

2. Description of the Related Art In various electronic devices, a microcomputer has a built-in A / D converter in order to achieve the function of calculating and outputting various sensor input signals. However, due to the demand for high performance and miniaturization of equipment,
Higher speeds and increased input signals are needed.

An A / D converter built in a conventional microcomputer has been realized by calculating an average value from A / D converted values by a program instruction.

For example, as shown in the flow chart of FIG.
The / D converted value is added, and when the number of times of addition reaches N, the added value is divided by N and the average value is stored.

In FIG. 3, first, the A / D conversion data is set to 1
After addition (process 20), it is determined whether or not N times have been added (process 21). If the addition has been made, the process proceeds to process 22, and if not, the process proceeds to process 26. In process 22, the added data is divided by N. In process 23, the data is stored and the process ends.

Here, the execution time of a standard 8-bit microcomputer is 15 μs for processes 20 and 21, 4 μs for process 22, and 5 μs for process 23.

As an example, if the flow of FIG. 3 is set to N-4 and it is replaced by a program instruction of an 8-bit microcomputer having an instruction execution time of 0.8 μs, it takes 84 μs.

Therefore, although the instruction execution time of the microcomputer is being accelerated by the improvement of the architecture and the progress of the semiconductor process, the needs of the applied equipment are
I want higher speed. For example, inverter control is a typical example.

[0009]

In such a conventional microcomputer, in order to obtain the average value of the A / D converted data N times, the addition and division are performed by the instruction of the program.

Therefore, a processing time of about 80 μs is required for an 8-bit microcomputer, and multi-channel A /
There is a problem that more processing is required when performing D conversion.

An object of the present invention is to solve the above problems and to provide a microcomputer capable of performing A / D conversion in a short time.

[0012]

A microcomputer of the present invention has an A / D converter for inputting an analog signal and converting it into A / D converted data, and an adder for adding the A / D converted data. A counter for counting the number of additions of the adder, a register for setting the number of additions of the adder in advance by software, a comparator for comparing the values of the counter and the register and outputting a coincidence signal, A selector for selecting an average value from an adder; a latch circuit for latching the output signal of the selector;
And a control unit for controlling the / D converter, the adder, and the counter.

[0013]

1 is a block diagram showing a microcomputer according to an embodiment of the present invention.

In FIG. 1, the configuration of the microcomputer of this embodiment includes an A / D converter 1 for inputting an analog signal and converting it into A / D converted data, and an adder 2 for adding the A / D converted data. A counter 3 for counting the number of times of addition of the adder 2, a register 5 for setting the number of times of addition of the adder 2 by software beforehand, and a value of the register 5 of the counter 3 are compared to generate a coincidence signal. Controls the comparator 4 that outputs, the selector 6 that selects the average value from the adder 2, the latch circuit 7 that latches the output signal of the selector 6, the A / D converter 1, the adder 2, and the counter 3. And a control unit 8 for controlling.

In FIG. 1, the data converted by the A / D converter 1 is added by an adder 2 to obtain an adder 2
The counter 3 counts the number of additions.

Next, when the value of the counter 3 of the value of the number of additions (average number) preset in the register 5 is matched by the comparison circuit 4, a signal is sent to the latch circuit 7, and the signal of the adder 2 The latch circuit 7 latches the data of the selector 6 which selects the average value according to the value of the register 5 from the added data, and sends the data to the internal bus 9.

Further, the A / D converter 1 starts A / D conversion in response to the signal output from the control unit 8 and clears the data in the adder 2 and the counter 3.

FIG. 2 is a diagram showing the operation of the adder 2 and the selector 6 in the embodiment of FIG.

In FIG. 2, the data output from the A / D converter 1 is 8-bit A / D converted data 10,
This is added to the adder 11.

Next, a method of obtaining average data from the added data of the adder 11 will be described. 2 times average data 12 is
The R-bit A / D conversion data 10 is added twice to the adder 11 to obtain the higher 8 bits of 9 bits. 4 times average data 1
3 is the higher 8 bits of the 10-bit data obtained by adding the 8-bit A / D conversion data to the adder 11 four times.

Accordingly, the adder 2 is added by the selector 6 of FIG. 1 according to the number of additions (average number) data of the register 5.
Average data can be selected from the addition data of.

[0022]

As described above, according to the present invention, an analog signal is inputted and converted into A / D converted data.
A converter, an adder for adding the A / D converted data, a counter for counting the number of additions of the adder,
A register that sets the number of times of addition of the adder in advance, a comparator that compares the values of the counter and the register and outputs a match signal if they match, a selector that selects an average value from the adder, and the selector By including a latch circuit for latching the output signal of the A / D converter and a control unit for controlling the A / D converter, the adder, and the counter, the average value of the A / D converted data realized by the instruction of the conventional program is hard-coded. With this, the processing time of the microcomputer can be reduced to about 1 μs or less from the conventional processing time of about 100 μs for a 4-bit microcomputer and about 80 μs for an 8-bit microcomputer per channel.

[Brief description of drawings]

FIG. 1 is a block diagram showing a microcomputer according to an embodiment of the present invention.

FIG. 2 is a diagram showing an operation of a sector shown in FIG.

FIG. 3 is a flow diagram of conventional program instructions.

[Explanation of symbols]

 1 A / D converter 2 adder 3 counter 4 comparison circuit 5 register 6 selector 7 latch circuit 8 controller 9 internal bus 10 8-bit A / D conversion data 11 adder 12 2 times average data (8 bits) 13 4 times average Data (8 bits) 20-23 processing

Claims (2)

[Claims] 1. An A / D converter that inputs an analog signal and converts it into A / D converted data, an adder that adds the A / D converted data, and a counter that counts the number of additions of the adder. A register for setting the number of times of addition of the adder in advance, a comparator for outputting a coincidence signal when the values of the counter and the register are compared and a match, and a selector for selecting an average value from the adder A microcomputer comprising: a latch circuit for latching the output signal of the selector; and a control unit for controlling the A / D converter, the adder, and the counter. 2. The microcomputer according to claim 1, wherein the control unit, the register and the latch circuit are all connected to an internal bus.