WO2002023351A9 - Functional pathway configuration at a system/ic interface - Google Patents

Abstract

The present invention relates generally to functional pathway configurations at the interfaces between integrated circuits (ICs) and the circuit assemblies with which the ICs communicate. More particularly, the present invention relates generally to the functional pathway configuration at the interface between a semiconductor chip including an IC (e.g., computer chips like microcontrollers and microprocessors) and the circuitry of a system including the chip. Even more particularly, the present invention relates to a 20-pin microcontroller functional pathway configuration for the interface between the microcontroller and a system in which the microcontroller is embedded.

Description

FUNCTIONAL PATHWAY CONFIGURATION AT A SYSTEM/IC INTERFACE

The present invention relates generally to functional pathway configurations at the interfaces between integrated circuits (ICs) and the circuit assemblies with which the ICs communicate. More particularly, the present invention relates generally to the functional pathway configuration at the interface between a semiconductor chip including an IC (e.g., computer chips like microcontrollers and microprocessors) and the circuitry of a system including the chip. Even more particularly, the present invention relates to a 20-pin microcontroller functional pathway configuration for the interface between the microcontroller and a system in which the microcontroller is embedded.

Background of the Invention The electronics industry is generally divided into two main segments: application products companies and semiconductor companies. The application products companies segment includes the companies that design, manufacture, and sell the wide variety of semiconductor-based goods. The semiconductor companies segment includes integrated circuit (IC) design companies (i.e., fabless companies which may design and/or sell semiconductor chips), foundries (i.e., companies that manufacture chips for others), and partially or fully integrated companies that may design, manufacture, package and/or market chips to application products companies.

There is a large range of semiconductor-based goods available across a broad spectrum of applications, i.e., goods which include one or more semiconductor devices, in applications ranging from manufactured printed circuit boards to consumer electronic devices (stereos, computers, toasters, microwave ovens, etc.) and automobiles (which, for example, include semiconductor devices in fuel injection, anti-lock brake, power windows and other on-board systems). Thus, as one might imagine, there also are a wide variety of semiconductor devices available to meet the various requirements of such products and applications. Perhaps the two most familiar types of semiconductor devices today arc microcontroller and microprocessor computer chips. Microcontrollers, which are the "brains" of a broad range of consumer and industrial applications, differ from microprocessors primarily from the standpoint of the end-user consumer. Typically, consumers concern themselves with the type of microprocessor in a product because the consumers will perceive different performance characteristics or results depending upon the type of microprocessor a product uses (e.g., personal computer applications). Microcontrollers, on the other hand, typically are embedded in an application system and do not enter into the equation when end-user consumers are making purchasing decisions.

Typically, semiconductor companies offer microcontrollers to products compames with a set of features and capabilities appropriate for a particular product or application. Thus, microcontrollers may have a broad range of features and capabilities, and semiconductor companies typically tend to offer their customers a wide range of microcontroller products to meet their customers' needs. For example, a semiconductor company may offer a family of products including a feature-rich "high-end" product (e.g., for automobile applications) and one or more "low-end" products including fewer features (e.g., for household appliance applications).

But while an end-user consumer, concerned only with whether a product works, might be indifferent as to the microcontroller device included in a product, the product designer and manufacturer certainly are not. Product companies generally will expend great efforts to ensure that their products work properly and that consumers receive value and remain satisfied. Thus, product companies tend to select microcontrollers for use in an application based on their features and capabilities, not to mention costs and other factors.

In view of such circumstances, there tends to be vigorous competition amongst semiconductor companies for microcontroller "design wins." In other words, at the design stage, when a products company is designing a product for a given application, semiconductor companies compete for having their microcontroller included in the product. Once a product company establishes a design and sets the- functional pathway configuration for the interface between a microcontroller and the system in which the microcontroller is embedded, the product company is less likely to change the configuration to accommodate another microcontroller having a different functional pathway configuration. Such configuration changes typically result in increased costs for the product company duo to the system in which the microcontroller is embedded having to be re-designed. While there are a number of factors involved in any decision to award a design win, one such factor comprises a semiconductor company's product "roadmap." Over time, end-user consumers generally tend to favor future generation consumer products having increased features at lower costs. Accordingly, product companies evaluating microcontroller products of two or more semiconductor companies today will consider whether the particular solutions being offered now will allow them to migrate easily from a basic first generation microcontroller to an enhanced future generation microcontroller having increased capabilities and features. Such migration - - without the products company incurring extensive system re-design costs - - in general is necessary if the products company is to offer the future generation products that consumers typically demand.

Accordingly, there remains a need for a simple and convenient functional pathway configuration for the interface between a microcontroller and the system in which the microcontroller is embedded, e.g. , that tends to promote increased performance with lower costs. Summary of the Invention

The present invention may address one or more of the problems set forth above. Certain possible aspects of the present invention are set forth below as examples. It should be understood that such aspects are presented simply to provide the reader with a brief summary of certain forms the invention might take, and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below.

In one embodiment of the present invention, a functional pathway configuration at the interface between an integrated circuit (IC) and the circuit assembly with which the IC communicates is provided. In a further embodiment, a functional pathway configuration at the interface between a semiconductor chip including an IC (e.g., computer chips like microcontrollers and microprocessors) and the circuitry of a system including the chip is provided. In still a further embodiment, a 20-pin microcontroller functional pathway configuration for the interface between the microcontroller and a system in which the microcontroller is embedded is provided. In one aspect, the present invention comprises a microcontroller including a plurality of pins. Advantageously, at least one pin comprises a power pin, at least one pin comprises a ground pin, and the remaining pins are input/output (I/O) pins, wherein each I/O pin may have one or more associated functions. The I/O pins may be analog, digital, or mixed-signal (can be analog or digital). Some I/O pins advantageously are multiplexed with one or more alternate functions for the peripheral features on the microcontroller so that in general when a peripheral is enabled that particular pin may not be used as a general purpose I/O pin.

In one embodiment, a microconcontroller in accordance with the present invention advantageously includes at least twenty pins, including two power pins; two ground pins; a first I/O port including eight pins; and a second I/O port including eight pins. Each pin may be adapted and described according to the function(s) dedicated to the pin, so that all or a portion of the pins together define a functional pathway configuration at the interface between the microcontroller and the system in which the microcontroller may be embedded. Alternately, in another embodiment, the present invention comprises a system for receiving such a microcontroller.

In accordance with the present invention, and depending upon the particular application involved, the IC with which a system interfaces may comprise a packaged IC. Examples of types of packaging include a dual in-line package (DIP), which may comprise molded plastic (PDIP) or ceramic (CERDIP); micro lead frame (MLF); pin grid arrays (PGAs); ball grid arrays (BGAs); quad packages; thin packages, such as flat packs (FPs), thin small outline packages (TSOPs), small outline IC (SOIC) or ultrathin packages (UTPs); lead on chip (LOC) packages; chip on board (COB) packages, in which the chip is bonded directly to a printed-circuit board (PCB); and others. However, for the sake of clarity and convenience only, and without limitation as to the scope of the present invention, reference will be made herein primarily to PDIP ICs. Tables la and lb describe two exemplary embodiments including the various functions that the microcontroller may perform, with the functions arranged by pin dedication. Of course the exact pin and function names used in any particular embodiment or application may vary depending upon the naming convention(s) selected. Table la is directed to an exemplary embodiment comprising an 18-pin microcontroller, while Table lb is directed to an exemplary embodiment comprising a 20-pin microcontroller. The embodiment described in Table la in general may be suited for applications such as temperature sensors, humidity sensors, light sensors and heart rate monitors, which may require only 10-bit A/D accuracy. The embodiment described in Table lb, on the other hand, may be suited for applications such as motor control, CO detectors, battery chargers, and chemical sensors, where 12-bit A/D accuracy may be required. In the latter case, there may be a need to provide a dedicated "noise free" power supply for the analog features in order to obtain the 12-bit A/D accuracy. Thus, the primary difference between the embodiments described in Tables la and lb is that the 20-pin embodiment of Table lb includes dedicated power and ground reference pins for analog features.

Tables 2a and 2b describe an embodiment of the present invention including two I/O ports, with each port including pins as shown in the Tables. Table 2a in general describes a first I/O port, and Table 2b in general describes a second I/O port. Each of the pins advantageously is adapted with circuitry to be dedicated to the functions as listed. Of course the exact form of the circuitry used to create such functionality and adapt such pins may vary depending upon the particular application involved. Without limitation as to the scope of the present invention. Table 3 describes exemplary circuitry in block diagram form for such an embodiment. Brief Description of the Drawings

Further objects and advantages of the present invention will become apparent upon reading the following detailed description and upon referring to the accompanying drawings in which:

FIG. 1A is a diagram illustrating an exemplary embodiment of an 18-pin microcontroller including a functional pathway configuration for the interface between the microcontroller and a system in which the microcontroller is embedded, in accordance with the present invention.

FIG. IB is a diagram illustrating an exemplary embodiment of a 20-pin microcontroller including a functional pathway configuration for the interface between the microcontroller and a system in which the microcontroller is embedded, wherein the power pins are tied together and the ground pins are tied together, in accordance with the present invention.

FIG. 2 is a diagram illustrating an alternative exemplary embodiment of a

20-pin microcontroller including a functional pathway configuration for the interface between the microcontroller and a system in which the microcontroller is embedded, in accordance with the present invention.

FIG. 3 is an illustration of an exemplary embodiment of a functional pathway configuration for the interface between an integrated circuit (IC) and a system with which the IC communicates, in accordance with the present invention. FIG. 4 is a diagram illustrating an exemplary embodiment of the integrated circuit shown in FIG. 3 wherein the IC comprises a microcontroller, in accordance with the present invention.

The present invention may be susceptible to various modifications and alternative forms. Specific embodiments of the present invention are shown by way of example in the drawings and are described herein in detail. It should be understood, however, that the description set forth herein of specific embodiments is not intended to limit the present invention to the particular forms disclosed. Rather, all modifications, alternatives, and equivalents falling within the spirit and scope of the invention as defined by the appended claims are intended to be covered. Detailed Description of Specific Embodiments

The description below illustrates embodiments of the present invention. For the sake of clarity, not all features of an actual implementation of the present invention are described in this specification. It should be appreciated that in connection with developing any actual embodiment of the present invention many application-specific decisions must be made to achieve specific goals, which may vary from one application to another. Further, it should be appreciated that any such development effort might be complex and time-consuming, but would still be routine for those of ordinary skill in the art having the benefit of this disclosure.

For the sake of clarity and convenience, aspects of the present invention are described in the context of various embodiments typically used in applications generally involving motor control, uninterruptible power supplies, sensors (e.g., smoke detectors, CO detectors), and signal conditioning. However, the present invention may also be useful in a wide variety of other applications, such as low-end white goods, where comparators can serve as a zero-crossing detector for the line voltage; simple A/D converters; as mouse controller devices, which need to accurately sense voltage transitions on motion wheels; as battery charger controllers which need simple A/D converters; etc.

Also, although the present invention may be used with discrete components, microprocessors, microcontrollers, and other devices and/or combinations thereof, for the sake of clarity and convenience reference is made herein only to microcontrollers.

Turning now to the drawings, and by way of general illustration, Figure 3 comprises a block diagram of an exemplary functionally configured interface between an integrated circuit and a system. Figure 4 shows in block diagram form an exemplary integrated circuit as illustrated in Fig. 3 comprising a microcontroller. The microcontroller advantageously may be embedded within the system shown in Fig. 3.

As shown in FIGS. 1 A, and IB, exemplary embodiments in accordance with the present invention comprise a PDIP 18-pin microcontroller and a PDIP 20-pin microcontroller respectively, having functional pathway configurations for the interface between the microcontroller and a system (not shown in FIGS. 1 A and IB; see FIG. 3) in which the microcontrollers are embedded. An alternate embodiment comprising a PDIP 20-pin microcontroller is shown in FIG. 2.

As shown in FIGS. 1A, IB and 2, the microcontroller is in general functionally configured with analog on one side of the vertical axis along the length of the package (as opposed to across the package). A configuration including such a feature has as an advantage an increased ability to isolate digital switching noise to one portion of the device. Such advantage may prove beneficial in some cases, e.g., to an applications engineer in situations where partitioning of the printed circuit board in which the microcontroller is to be mounted would prove to be advantageous. In general, such an arrangement permits analog signals being wired to a port on one side portion of the device, and digital signals being wired to a port on the other side portion (which may be viewed along any axis, partition or other boundary).

In the embodiments shown, the OSCl and OSC2 pins comprise an exception to the above generality concerning separation of analog and digital pins. The OSCl and OSC2 pins tend to generate noise, and thus advantageously are not disposed on the analog side of the device. Further, the OSC2 pin advantageously is disposed between the OSCl pin and a power pin. Placing the OSC2 pin next to an I/O pin might possibly cause a glitch or disruption of the system clock. I/O pins can have high currents and fast transition times which can inductively or capacitively couple to other signals. The OSC2 output, having low impedance, might be affected in such an environment. The OSCl pin, on the other hand, advantageously goes through an internal buffer, and thus is not as susceptible to such coupling although disposed alongside an I/O pin.

Further the RA6 and RA7 pins are dedicated to OSC pins because the RB pins are required for an 8-bit port for byte-wise data transfer regardless of OSClllator selection, and multiplexing of the OSC pins precludes their functioning as part of an 8-bit port.

In accordance with the present invention, a subset of the pins may be fixed in particular locations to meet the compatibility requirements of existing development tools intended to be used with the device. For example, in the embodiment of the present invention shown in FIG. 2, the RB6, RB7, NDD, VSS, MCLR, ANDD and ANSS pins comprise such a subset.

The present invention has been described in terms of exemplary embodiments. In accordance with the present invention, the parameters for a system may be varied, typically with a design engineer specifying and selecting them for the desired application. Further, it is contemplated that other embodiments, which may be devised readily by persons of ordinary skill in the art based on the teachings set forth herein, may be within the scope of the invention, which is defined by the appended claims. The present invention may be modified and practiced in different but equivalent mamiers that will be apparent to those skilled in the art having the benefit of the teachings set forth herein.

No limitations are intended to the details or construction or design shown herein, other than as described in the claims appended hereto. Thus, it should be clear that the specific embodiments disclosed above may be altered and modified, and that all such variations and modifications are within the spirit and scope of the present invention as set forth in the claims appended hereto.

TABLE la.

Note 1 : Bit programmable pull-ups.

TABLE lb.

Note 1 : Bit programmable pull-ups.

TABLE 2a.

TABLE 2b

Note 1 : Bit programmable pull-ups.

TA6LE 3

PI J MAi E EX&WLAR.Y BLOCK CIRCUIT Rγ

RA0/AN0, RA1/AN1/L.VDIN

RA2/AN2/VREF-/VRL AND RA3AN3/VREF+/VRH

TA6L 3 Ccont'v)

π- fJ er E εHPCΛΛY fcVoCK CIRCUITRY

RA7/OSC1/C KIN

RB0/AN4ΛNT, RB1/AN5SS

TABLE 3 ( CONT'D)

TASie 3 ( ONT'D)

Claims

WHAT IS CLAIMED IS:

1. A microcontroller having the following pin-out:

1C

A microcontroller having the following pin-out:

wherein the NSS ¹⁾ and VSS⁽²⁾ pins are tied together and the NDD ¹⁾ and NDD⁽²⁾ pins are

tied together.

3. A system/IC interface forming a functional pathway configuration including at least two input/output (I/O) ports comprising:

a first port including a first set of eight pins PI, P2, P3 ... P8, each of the eight pins of the first set having dedicated functions as follows:

and

a second port including a second set of eight pins P9, P10, PI 1 ... PI 6,

each of the eight pins of the second set having dedicated functions as follows:

A microcontroller having the following pin-out:

ιc