Registers – Systems controlled by data bearing records – Credit or identification card systems
Patent
1993-04-06
1994-11-15
Shepperd, John
Registers
Systems controlled by data bearing records
Credit or identification card systems
235492, G06K 19073
Patent
active
053650476
ABSTRACT:
The invention provides an IC card which performs control of allowing or inhibiting input of a clock signal externally of the card via no CPU. In the present IC card, those ones of a CPU 1a, a UART 7a, a timer 3 and an EEPROM 5a which require the clock signal for operation generate operation signals. In accordance with these operation signals, a clock control circuit 8 performs control of allowing or inhibiting input of the clock signal externally of the card without intervention of the CPU 1a. Supply of the clock signal to the CPU 1a is stopped upon an STP command executed by the CPU 1a, and resumed in accordance with any of start-up select conditions set by the CPU 1a and corresponding one of operation end signals from the UART 7a, the timer 3 and the EEPROM 5a.
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Mitsubishi Electric Data Sheet for microcomputer chip M38002M4-XXXSP/FP.
Mitsubishi Denki & Kabushiki Kaisha
Shepperd John
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