Abstract A display data holding circuit holds character data, and serially outputs character data. A display data switching circuit inputs character data outputted from the display data holding circuit to a display data holding circuit again, and the display data switching circuit receives a switching command of display data, thereby switching character data outputted from the display data holding circuit to new character data to be inputted to the display data holding circuit. A display data latching circuit synchronizes character data outputted from the display data holding circuit with the latch pulse to be latched. A latch pulse generating circuit generates a latch pulse. A modulo N counter counts a number of clock pulses outputted from the latch pulse, and generates a reset pulse every time when the count of N number of clock pulses is ended, and the modulo N counter receives a forced reset signal, thereby generating a reset pulse. A control section supplies the switch command of display data to the display data switching circuit, and the forced reset signal to the modulo N counter at the same time.
A character data writing device comprising: a latch pulse generating section for generating clock pulses and a latch pulse; a display data holding circuit for holding character data, and serially outputting said character data; a display data switching circuit for inputting the character data outputted from said display data holding circuit into said display data holding circuit again and for receiving a switching command of display data, thereby switching character data outputted from said display data holding circuit to new character data to be inputted to said display data holding circuit; a display data latching circuit for latching character data outputted from said display data holding circuit in synchronism with the latch pulse and for supplying the latched character data to a character data display section; a modulo N counter for counting a number of clock pulses generated by said latch pulse generating section and for generating a reset pulse every time a count of N clock pulses is ended, and said modulo N counter receiving a forced reset signal, and also generating a reset pulse upon receiving said forced reset signal, said latch pulse generating section generating said latch pulse upon each generation of said reset pulse by said modulo N counter; and a control section for supplying the switching command of said display data to said display data switching circuit, and for supplying the forced reset signal to said modulo N counter at the same time, whereby a latch pulse is immediately generated and character data is immediately latched in said display data latching circuit.
Claim 2
Dependent Claim
257 words
A character data writing device comprising: a latch pulse generating section for generating clock pulses and a latch pulse; a display data holding circuit for holding character data, and serially outputting said character data; a display data switching circuit for inputting the character data outputted from said display data holding circuit into said display data holding circuit again and for receiving a switching command of display data, thereby switching character data outputted from said display data holding circuit to new character data to be inputted to said display data holding circuit; a display data latching circuit for latching character data outputted from said display data holding circuit in synchronism with the latch pulse and for supplying the latched character data to a character data display section; a modulo N counter for counting a number of clock pulses generated by said latch pulse generating section and for generating a reset pulse every time a count of N clock pulses is ended, and said modulo N counter receiving a forced reset signal, and also generating a reset pulse upon receiving said forced reset signal, said latch pulse generating section generating said latch pulse upon each generation of said reset pulse by said modulo N counter; and a control section for supplying the switching command of said display data to said display data switching circuit, and for supplying the forced reset signal to said modulo N counter at the same time, whereby a latch pulse is immediately generated and character data is immediately latched in said display data latching circuit.
Claim 3
Dependent Claim
76 words
The character data writing device according to claim 1, wherein said display data holding circuit comprises a plurality of shift registers cascade-connected, character data outputted from said display data switching circuit is inputted to a first shift register, character data outputted from said first shift register is inputted to said display data latch circuit and a last shift register, and character data outputted from said last shift register is inputted to said display data switching circuit.