JPS623756Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a segment lighting circuit that reduces the number of input/output ports required for display.

The display panel 1 for a microprocessor that displays the time and day of the week does not require input terminals for each display segment, but has block designation terminals b1 to b7 that designate seven blocks corresponding to the day of the week display, and one for displaying numbers. 7 terminals a1 to a7, 7 terminals a8 to a14 for day of the week display, terminal a15 for spacer display,
Segment input terminals a1 to a18 consisting of two terminals a16 and a17 for AM/PM display and a terminal a18 for power-on display are provided, and signals are selectively input to each terminal to display segments at a predetermined period for each block. lights up at high speed. A conventional display panel lighting circuit will be explained below with reference to FIG. The microprocessor 2 is equipped with an input port I, an output port O, an input/output port IO, and when displaying, the output port O and the input/output port IO are used to input 8-bit display data to the segment input terminals a1 to a18. The input/output ports for deriving timing pulses are connected to the block designation terminals b1 to b7 as shown in the figure. That is, the 7 terminals a1 to a7 for number display are connected to the 7 output ports O1 to O7, the remaining output port O8 is commonly connected to the 7 terminals a8 to a14 for day of the week display, and the remaining segment input terminals a15 to a1
8 are separately connected to four output ports O5 to O8 among the seven output ports described above. Therefore, when displaying such a conventional circuit, input/output port IO1
~The display data is transmitted from the output ports O1 to O8 to each segment signal input terminal a1 to a18 in synchronization with the timing pulses periodically and sequentially derived from IO7.
The conventional circuit requires as many as seven input/output ports for displaying time. Therefore, when controlling program reservations,
Not only is the number of control outputs limited, but the lighting period is also limited to 1/7, which reduces the amount of display light.

Therefore, in view of the above-mentioned points, the present invention aims to provide a segment lighting display circuit that reduces the number of input/output ports for display and allows diversification of control using the remaining input/output ports.

The present invention will be described below with reference to an illustrative embodiment.

In this embodiment, as shown in FIG.
is connected to a common input/output port IO1 and the three blocks mentioned above are displayed at the same timing, thereby reducing the number of input/output ports by two. Therefore, in this embodiment, the first block has a terminal a14 for Sunday display, a terminal a13 for power-on display, a terminal a13 for Monday display of the second block, terminals a16 and a17 for AM/PM display, and terminals a16 and a17 for AM/PM display of the fifth block. Terminal a10 for Thursday display and terminal a15 for spacer display are each connected to seven output ports O1.
~ Separately connected to O7. Therefore, theoretically, seven segment signal input terminals a14, a1
8, a13, a16, a17, a10 and a15
It is sufficient to change the program so that the display data that is input to the computer is output at the same timing.

However, a 4-bit microprocessor using a PLA (programmable logic array) can normally derive fixed display data in only 24 ways. Therefore, it is difficult to freely combine and derive 8-bit display data.

Therefore, in this embodiment, special characters [such as "E" (abbreviation for error operation) and "P" (abbreviation for position)] and numbers are stored in the ROM as fixed 7-bit display data.
Instead of storing each bit of the display data internally and reusing each bit output of the display data for other displays, the PLA is effectively utilized by displaying the day of the week separately in terms of timing. Therefore, when displaying, the day of the week is first displayed by combining the outputs of the input/output ports and the outputs of the output ports, and then the remaining segments are displayed sequentially according to the timing pulses derived from the input/output ports. .

Therefore, according to this embodiment, the lighting period is reduced to 1/6, but the number of input/output ports required for display can be reduced by two, and the remaining input/output ports can be used to turn on/off the power.
OFF control output Muting control output when changing channels, initializer control output for resetting channel position, shift pulse control output for setting channel position,
A buzzer control output for driving an alarm buzzer is independently derived, and an AC voltage for clocking is inputted from the remaining input/output port O10.

Therefore, according to the present invention, since the number of input/output ports for display is reduced, control can be diversified, and the effect is great.

[Brief explanation of the drawing]

FIG. 1 shows a conventional circuit connection, and FIG. 2 shows an example of a circuit according to the present invention. Explanation of main drawing numbers, O1 to O8...output ports,
IO1~IO10...Input/output port, a1~a18
...Segment signal input terminal, b1 to b7...Block designation terminal.

Claims (1)

[Scope of utility model registration request] A numeric display section that displays hours and minutes using at least four digits, a space display section that separates the hour and minute display, and an AM/minute display section.
A display panel in which the afternoon display section is arranged in seven blocks in correspondence with the day of the week display section, and a timing pulse is periodically input to the block designation terminal corresponding to the block, and each block is displayed by lighting in synchronization with the timing pulse. and a microprocessor that controls lighting of the display panel, a display segment signal input terminal of the display panel and an output port of the microprocessor, and a block designation terminal of the display panel and an input/output port of the microprocessor. A segment lighting circuit characterized in that the block designation terminals of display blocks that do not include a numeric display section are connected to a common output port in a display circuit in which a connection circuit is connected to each segment.