Integrated circuit with microprocessor and programmable internal clock

• US 5,036,300 A
• Filed: 07/03/1990
• Issued: 07/30/1991
• Est. Priority Date: 07/07/1989
• Status: Expired due to Term

• Current Assignee: SGS-Thomson Microelectronics (STMicroelectronics NV)
• Original Assignee: SGS-Thomson Microelectronics (STMicroelectronics NV)
• Inventors: Nicolai, Jean
• Primary Examiner(s): MIS, DAVID C
• Application Number:
  US07/547,876
• Time in Patent Office: 392 Days
• Field of Search: 331/1 A, 331/34, 331/111, 331/143, 331/175, 331/176, 331/177 R, 331/177 V, 331/108 C, 331/179, 331/DIG. 3
• US Class Current: 331/143
• CPC Class Codes: G06F 1/08 Clock generators with changeable or programmable clock frequency

Abstract

The disclosure concerns the manufacture of integrated circuits and, more precisely, that of integrated circuits containing a signal processor. To be able to make a purely internal clock in an integrated circuit, wherein this clock does not require any external adjusting elements connected to terminals of the circuit, the clock is designed to include an internal oscillator, the frequency of which is adjustable by a register, it being possible for the register to be loaded by the processor. The frequency of the oscillator may be adjusted to compensate for the uncertainty over the natural frequency of the oscillator (which is subject to technological fluctuations). It may also be used to adjust the frequency as a function of an application or of the environment of the circuit. The contents of the register may come from a non-volatile memory containing individual data on the circuit.

Claims

1. An integrated circuit including a processor and an oscillator integrated into the same substrate as the processor, said integrated circuit also including a data register capable of being loaded by the processor, said oscillator acting as a clock for the processor and being a relaxation oscillator including a capacitor and current sources for charging and discharging the capacitor and the register controlling the value of the currents for charging and discharging the capacitor to adjust the frequency of the oscillator, wherein the register is loaded by the processor from an electrically programmable nonvolatile memory, made on the same integrated circuit substrate and containing a frequency correction data.

2. An integrated circuit according to claim 6, wherein the nonvolatile memory contains individual pieces of data for the correction of the integrated circuit, these pieces of data being obtained by the testing of the integrated circuit after manufacture, so as to take account of the fluctuations of manufacturing parameters of the circuit.