CN1499632A

CN1499632A - Multifunctional pin circuit

Info

Publication number: CN1499632A
Application number: CNA021451435A
Authority: CN
Inventors: 陈后鹏
Original assignee: Shanghai Beiling Co Ltd
Current assignee: Shanghai Beiling Co Ltd
Priority date: 2002-11-07
Filing date: 2002-11-07
Publication date: 2004-05-26
Anticipated expiration: 2022-11-07
Also published as: CN1324706C

Abstract

The pin possesses three output ends A, B and C. An end through a clock signal strobe module is connected to the pin. B end through a high-level strobe module is connected to the pin. C end is leaded out directly from the pin. The said clock signal strobe module is composed of a 4 bits binary counter and a state clamping trigger. The high-level strobe module is composed of 32 frequency dividing circuit and a feedback state control circuit. Based on different signals provided for the pin from external, the multifunctional pin circuit provides different control electrical level for controlling other pins or internal circuits.

Description

Multi-functional pin circuit

Technical field

The invention belongs to a kind of pin circuit that can realize multinomial function selecting.

Technical background

When the large-scale integrated circuit of design, owing on the limited silicon chip of size, need to be provided with ten hundreds of circuit units, therefore this means the integrated level that will improve circuit as much as possible, yet for on-chip pin, since silicon area finiteness and manufacturing process on limitation, the number of pins increase will far fall behind the raising with circuit level, so each on-chip pin all needs through well-designed, so often having some function pin is forced to give up, but in order to realize designing requirement, the designer has to find out the pin that other method comes equivalence to be forced to give up, thereby will make circuit design too complicated, development cost increases, and causes unnecessary waste.

Summary of the invention

The technical issues that need to address of the present invention are a kind of multi-functional pin circuit, it can provide the difference of signal according to the outside for this pin, control level different, that can control other pin or internal circuit is provided respectively, thereby reduced the required number of pins of device, simplify circuit design, saved unnecessary development cost.

For solving the problems of the technologies described above, the technical solution used in the present invention is:

A kind of multi-functional pin circuit, this pin circuit has three output terminals A, B and C, and wherein the A end links to each other with pin by a clock signal gating module, and the B end is connected with pin by a high-level strobe module, the C end is directly drawn by pin.

Described clock signal gating module is clamped down on trigger by 4 binary counters and a state and is formed; Described 4 binary counters mainly are formed by connecting by 4 d type flip flops and logic gates, wherein, pin links to each other with the clock signal terminal of d type flip flop, when pin connects high level or low level, 4 binary counters are not worked, and pin is when connecing clock signal, and 4 binary counters begin counting; Described logic gates includes three and door, a not gate and three XOR gate; Described state is clamped down on trigger and is made up of a d type flip flop and an OR circuit, and wherein the Q_ of d type flip flop end links to each other with the D end, and clock signal terminal connects the output of described 4 binary counters.

Described high-level strobe module is made up of one 32 frequency dividing circuit and a feedback state control circuit; Described 32 frequency dividing circuits are interconnected by 4 d type flip flops and form, and wherein import the D end and link to each other with the Q_ end, and the Q_ of last trigger end is connecting the clock signal terminal of next trigger; Described feedback control circuit is made up of an OR circuit and a master clock input, high-level strobe module output B lead-in wire and above-mentioned master clock input lead-in wire insert above-mentioned OR circuit, and the output of this OR circuit connects the clock signal terminal of the first order d type flip flop of 32 frequency dividing circuits; Pin links to each other with the reset terminal of d type flip flop; Described feedback state control circuit is made up of a d type flip flop and an OR circuit, and wherein the Q_ of d type flip flop end links to each other with the D end, and clock signal terminal connects the output of described 32 frequency dividing circuits, and pin links to each other with the reset terminal of d type flip flop.

Owing to taked above-mentioned scheme, the advantage that the present invention is compared with prior art had is:

Owing to be provided with clock signal gating module and high-level strobe module in the multi-functional pin circuit of the present invention, make this multi-functional pin circuit that the difference of signal can be provided for this pin according to the outside, control level different, that can control other pin or internal circuit is provided respectively, the function that clock signal gating module realizes is, when pin was connected to high level or low level, output was low level; When pin was connected to clock signal, output was high level; And the function that high-level strobe module realizes is that when pin was connected to low level or clock signal, output was low level; When pin was connected to high level, output was high level.

By pin is added different signals, realized logic control like this to same circuit in inside or different circuit.In the circuit design of reality, realized that with a pin control of function is selected more than two kinds, thereby reduced the required number of pins of device, simplified circuit design, save unnecessary development cost.

Description of drawings

Below in conjunction with the drawings and specific embodiments the present invention is described in further detail:

Fig. 1 is the schematic block diagram of the multi-functional pin circuit of the present invention;

Fig. 2 is the circuit theory diagrams of clock signal gating module in the multi-functional pin circuit of the present invention;

Fig. 3 is the oscillogram of clock signal gating module output high level in the multi-functional pin circuit of the present invention;

Fig. 4 is the circuit theory diagrams of high-level strobe module in the multi-functional pin circuit of the present invention;

Fig. 5 is the oscillogram of high-level strobe module output high level in the multi-functional pin circuit of the present invention;

Fig. 6 is the truth table of the multi-functional pin circuit of the present invention.

Embodiment

In order to reduce total number of pins, realize that it is a kind of very natural selections that a pin is finished a plurality of functions.This multi-functional can be that a pin is realized the output of inner different circuit respectively under the control of a control circuit, or realize the bidirectional port of this pin, promptly this pin can be used as input pin, also can be used as the function of output pin; Also can be a pin externally under the control of signal, select inner different circuit module to go to realize different functions respectively.

As shown in Figure 1, the multi-functional pin circuit of the present invention is made up of pin one (representing pin with Pin in the drawings), clock signal gating module 2, high-level strobe module 3, this pin circuit has three output terminals A, B and C, wherein the A end links to each other with pin one by clock signal gating module 2, and the B end is connected with pin one by high-level strobe module 3, and the C end is directly drawn by pin one.

The effect of output terminals A has two, the one, for the signal C that is input to internal circuit of pin one provides control signal CE, for example, signal A receives the control end CE that multichannel is selected output device or triple gate, when the input signal of pin was high/low level, signal C did not pass through, and when the signal of pin connection is clock (Clock) signal, the device of A control is open-minded, and signal C passes through; The 2nd, for other Enable Pin provides control signal.B also provides two class control levels, and when pin connect low level/clock (Clock) signal, output B was a low level, and when pin connect high level signal, output B was a high level.Pin circuit has just been realized the various control function like this.

As shown in Figure 2, clock signal gating module is clamped down on trigger by 4 binary counters and a state and is formed in the multi-functional pin circuit of the present invention; Described 4 binary counters mainly are formed by connecting by 4 d type flip flops and logic gates, wherein, pin one links to each other with the clock signal terminal of d type flip flop, when pin connects high level or low level, 4 binary counters are not worked, and pin is when connecing clock signal, and 4 binary counters begin counting; Described logic gates includes three and door, a not gate and three XOR gate; Described state is clamped down on trigger and is made up of a d type flip flop and an OR circuit, and wherein the Q_ of d type flip flop end links to each other with the D end, and clock signal terminal connects the output of described 4 binary counters.

After powering on, reset signal Reset makes whole d type flip flops (DFFR) reset to 0; When pin i connect high/low level, counter did not have count pulse, was output as low level 0, because state is clamped down on the effect of trigger, output circuit is latched in low level; When pin one connects clock signal, 4 binary counters begin counting, when the rising edge of the 16 pulse of clock signal, a counter output pulse (Counter), or door output high level, promptly clamp down on clock signal of d type flip flop in the trigger to state, make the output circuit state turnover, because state is clamped down on the effect of trigger, output terminals A is latched in high level state.Corresponding oscillogram as shown in Figure 3.

As shown in Figure 4, high-level strobe module is made up of one 32 frequency dividing circuit and a feedback state control circuit in the multi-functional pin circuit of the present invention; Described 32 frequency dividing circuits are interconnected by 4 d type flip flops and form, and wherein import the D end and link to each other with the Q_ end, and the Q_ of last trigger end is connecting the clock signal terminal of next trigger; Described feedback control circuit is made up of an OR circuit and a master clock input, high-level strobe module output B lead-in wire and above-mentioned master clock input lead-in wire insert above-mentioned OR circuit, and the output of this OR circuit connects the clock signal terminal of the first order d type flip flop of 32 frequency dividing circuits; Pin links to each other with the reset terminal of d type flip flop; Described feedback state control circuit is made up of a d type flip flop and an OR circuit, and wherein the Q_ of d type flip flop end links to each other with the D end, and clock signal terminal connects the output of described 32 frequency dividing circuits, and pin links to each other with the reset terminal of d type flip flop.

The pin one input signal is directly inputted to the reset terminal Reset of this circuit, when pin one connects low level/clock signal, as long as this clock cycle less than 15 master clock (Mclock) cycles, the level of output B is a low level; When pin one connects high level, rising edge in the 16 cycle of master clock (Mclock), the level of output B is exactly a high level, this high level feeds back to or door, because high level is or the control level of door, so the input end of clock of first d type flip flop of this 32 frequency dividing circuit is always high level, promptly this d type flip flop does not have clock signal, because the effect of feedback state control circuit, output B is latched in high level.Corresponding oscillogram as shown in Figure 5.

According to the difference of pin Pin connection signal, the truth table of the output terminals A of pin circuit, B and C as shown in Figure 6.When the pin input low level, A, B and C end are output as low level; When the pin input high level, A holds output low level, and B and C end are output as high level; When pin is input as clock signal, A end output high level, the B end is low level, the C end is clock signal.By pin is added different signals, just realized logic control like this to same circuit in inside or different circuit.

Claims

1, a kind of multi-functional pin circuit, it is characterized in that: this pin circuit has three output terminals A, B and C, wherein the A end links to each other with pin (1) by a clock signal gating module (2), and the B end is connected with pin by a high-level strobe module (3), and the C end is directly drawn by pin.

2, multi-functional pin circuit according to claim 1 is characterized in that: described clock signal gating module (2) is clamped down on trigger by 4 binary counters and a state and is formed.

3, multi-functional pin circuit according to claim 1 is characterized in that: described high-level strobe module (3) is made up of one 32 frequency dividing circuit and a feedback state control circuit.

4, multi-functional pin circuit according to claim 2, it is characterized in that: described 4 binary counters mainly are formed by connecting by 4 d type flip flops and logic gates, wherein, pin links to each other with the clock signal terminal of d type flip flop, when pin connects high level or low level, 4 binary counters are not worked, and pin is when connecing clock signal, and 4 binary counters begin counting; Described logic gates includes three and door, a not gate and three XOR gate.

5, multi-functional pin circuit according to claim 2, it is characterized in that: described state is clamped down on trigger and is made up of a d type flip flop and an OR circuit, wherein the Q_ of d type flip flop end links to each other with the D end, and clock signal terminal connects the output of described 4 binary counters.

6, multi-functional pin circuit according to claim 3 is characterized in that: described 32 frequency dividing circuits are interconnected by 4 d type flip flops and form, and wherein import the D end and link to each other with the Q_ end, and the Q_ of last trigger end is connecting the clock signal terminal of next trigger; Described feedback control circuit is made up of an OR circuit and a master clock input, high-level strobe module output B lead-in wire and above-mentioned master clock input lead-in wire insert above-mentioned OR circuit, and the output of this OR circuit connects the clock signal terminal of the first order d type flip flop of 32 frequency dividing circuits; Pin links to each other with the reset terminal of d type flip flop.

7, multi-functional pin circuit according to claim 3, it is characterized in that: described feedback state control circuit is made up of a d type flip flop and an OR circuit, wherein the Q_ of d type flip flop end links to each other with the D end, clock signal terminal connects the output of described 32 frequency dividing circuits, and pin links to each other with the reset terminal of d type flip flop.