Abstract: The PSoC microprocessor is on one kind of scene programmable piece which Cypress Corporation promotes the system. Internal has the general simulation and the digital module, the user may according to the development need, the optional calling module, realizes the composite signal array dynamic disposition. In the article elaborated in detail its out of the ordinary integrated development environment, the composite signal array’s system-level integration way, dynamic may redeploy the function, and take the CY8C24223 chip’s in feeling smoke fire detector application as but actually, explains the above function outstanding.
Key word: On the programmable piece the system PSoC composite signal array dynamic disposition feeling smoke fire surveys
The PSOC microprocessors have many series, the multi-specification application chip, satisfies the different user the different level need, like CY8C26XXX/CY8C24XXX/CY8C22XXX and so on. Its appearance enabled the designer to get rid of the board level electron system design method level to enter the chip level electron system design gradually, reduced monolithic integrated circuit’s variety and the specification, simultaneously was more advantageous in the new product develops and turns to a new generation. Compares with the homogeneous price’s ordinary monolithic integrated circuit, its rich internal resources, the novel design contact surface, the nimble design way, the simple programming skill cause it to have the characteristic extremely. In the article take CY8C24223 as the example, introduces one kind of model application - - based on the PSoC programmable piece on system’s feeling smoke fire detector. It to the smog change signal’s enlargement, processing, a/d conversion function will integrate microprocessor’s interior to complete, reduced the chip periphery component, enhanced the system whole integrated performance.
1 internal resources and development environment
1.1 internal resources introductions
The PSoC interior has a high speed M8C essence, to dodge quickly the memory and the SRAM data memory, as well as may carry on many kinds of dispositions the analog module arrays and the digital module array; The essence uses the Haryard structure, has the independent program memory and the data-carrier storage main line, the processor operating frequency may achieve 24 MHz. Regarding the different series, on the different model’s piece the system, its internal resources deployment is different. Take the CY8C24223 chip as the example, the interior has 4 KB Flash as well as 256 B internal SRAM data-carrier storage; 4 digital modules, 6 analog modules; 16 general I/0 mouths, the maximum output electric current may reach 25 mA, each I/O mouth pin may through the programming establishment, all I/O mouth pin be able to take the interrupt source; Has the memory byte invariable EEPROM module and the ISSP serial programming function.
1.2 integrated development environment lDE
Uses in PSoC integrated development environment PSoC Designer is one kind of function complete, based on the Gul design tool suite. It divides into the equipment edition subsystem, the application edition subsystem and the debugging routine subsystem. Its contact surface will act according to the different subsystem to divide Cheng Duoge the active window. And most characterful is the equipment edition subsystem, has the suitable flexibility and the feasibility, like chart l shows.
The user may through the choice and the laying aside user module, the disposition parameter, the linking module, the definition pin function, the production completes the equipment edition work finally using document API. In product development triturating, regardless of being changes the principle of design to change the design variable, does not need on the PCB board to carry on, but only need be possible to carry on with the aid of the simple mouse click option to the silicon chip redeploys, fast, completes the product the function block to select as well as between the function block segment simply.
On 2 PSoC pieces systematic development key
2.1 composite signal array system-level integration
User’s analog module array and digital module array’s configurable is this programmable pieces on systematic most major characteristic, it is different with FPGA or on the CPLD embedded piece the system. FPGA and CPLD are carry on the scene editor to the logical gate array, but PSoC the `microprocessor not can only carry on the dynamic disposition to the digital module, simultaneously can also carry on the dynamic disposition to the analog module, realizes the composite signal array system-level integration.
When application, on the piece in system’s digital module array may dispose many kinds of functions, like fixed time/counter, UART, SPI, CRC generator, PWM and so on; The analog module arrays may dispose have different working ADC, programmable gain amplifier PGA, comparator, programmable filter, DAC and so on. Through uses the digital module disposition the timer to take ADC the sampling frequency and so on similar method, realizes the digital module array and the analog module array integrated application, enables the PSoC microprocessor to have the formidable composite signal array system-level integration function.
In the PSoC microprocessor’s module function, the simple the composite signal integration function’s application is a/D switch. PSoC the microprocessor support many kinds of A/D switches, like 14 increasing types, 11 △-∑ADC, 8 approach type ADC and 6 SAR-ADC gradually. The user may act according to a/D conversion accuracy and the switching time design requirements, the establishment different working A/D module. Take disposes 8 △-A/D switches as the example, the switch must take microprocessor’s internal resources is: 1 digital module, 1 switch electric capacity simulates the SC module, 1 exterior analog input pin, as well as produces 8 byte internal RAM which and 143 byte Flash 8 △-ΣA/D switch application procedure API needs.
Figure 2 is a 8 △-∑A/D switch’s structure diagram. It by the analog switch electric capacity SC module, 8 timers and sampler each is composed. The analog switch electric capacity SC module completes the signal gathering and the transformation works; 8 timers use in the layout data clock signal controlling the sampling speed, the sampling speed are O.125 ksps~31.25 ksps; △-∑ in the ADC sampler in fact is SINC2 filter. In x territory, its transfer function is as follows:
In which n is the sampling rank. This sampling filter are complete by the software and hardware joint operation. Type (1) denominator part’s two integral item realizes by the hardware, the molecular part’s two difference sampling rate computation realizes by the software.
2.2 dynamic may redeploy the function
The embedded system designers use the PSoC construction the flexibility, dynamic founds many kinds of dispositions on the single component, this is on the PSoC programmable piece the systematic another major characteristic. Conceivable. This is similar to with FPGA carries on the design, since when systems operation, may also carry on the promotion to its hardware or redeploy. The tendency redeploys the function to enable the designers many times, in the redundant use chip simulation and the digital resources, but does not need to increase the cost and the part storehouse.
Below take the PGA module as an example, explains its dynamic disposition function.
(1)PGA module resources and parameter disposition
PSoC in microprocessor’s PGA module has the high input impedance, the width band width gain and may the dynamic disposition gain parameter, its function establishment in above simulation run-on time CT module foundation. Through controls register’s disposition to CT module’s three, supports the gain output or the weaken output, disposition signal input the port and the output port. Completes a PGA disposition, must take microprocessor’s internal resources is: 1 CT run-on time analog module, 1 exterior I/O pin as well as produces 52 byte Flash which PGA application procedure API needs. Figure 3 is the programmable gain amplifier PGA structure diagram.
Regarding the gain ≥1 operational amplifier, the programmable electricity chokes, Rb, the Ra series, a Rb end company arrives at amplifier’s out-port. Ra end connection VGND, VGND has the multiple options, the user may meet according to the different need VGND the digit, the simulation, the internal band gap voltage or exterior loses the person voltage signal; Rb and the Ra middle coupling end company arrives at amplifier’s negative feedback to lose the person end. From this, may promote amplifier’s transmission function to be as follows:
Regarding increases <1 the weaken operational amplifier, must dispose the voltage follower, a programmable resistance Rb end company arrives at amplifier’s out-port, a Ra end company arrives at VGND, Rb and the Ra middle coupling end company arrives at the user module out-port. From this, may promote negative increases amplifier’s transmission function to be as follows:
(2)PGA module dynamic entourage
In the application, the PGA analog module’s input end, the gain parameter, the out-port may carry on the dynamic disposition. Its input end may with a simulated signal input pin connection, may also dynamic connect this PGA module with another simulated signal input pin, completes in the different time to the multi-channel simulator input enlargement work, but does not need on the single component to dispose many PGA modules; Its gain parameter may also the dynamic regulation (from negative increase 0.06 time to increase 48 times to most Taisho), has developed the PGA module input voltage scope extremely conveniently; Its out-port may also demand must dynamic receive the output pin, a/D module input end or the filter. Its dynamic reshuffle part’s procedure is as follows:
M8C_SetBankl
and reg[ABF_CR0].OOh; Establishes the Po[O] pin and the internal PGA module connection
M8C_SetBank0
mov A, PGA_1_G5_3
call PGA_1_setGaln; Transfers PGA the module the APl procedure, establishes PGA
; The module enlargement factor is 5.33 times
lcall sample; Enlarges after the P0[O] pin’s simulator input carries on
; Sampling
lcall delay50ms; Time delay
M8C_SetBartkl
or reg[ABF_CR0],80h; The tendency disposes the PGA module and the Po[1] pin connection
M8C_SetBankO
mov A, PGA_l_G48_O
caIl PGA_1_setGain; The tendency disposes the PGA module the enlargement factor is 48 times
lcaIl samplc; Enlarges after the P0[1] pin’s simulator input carries on the sampling
3 CY8C24223 in feeling smoke fire detector’s application
The light inductance smoke fire detector application scattering principle, transforms the smog density’s change as the weak electro-optical signal, after enlargement and filter processing, carries on A/D to transform, completes to the smog density examination, realizes the fire warning function. Feels smoke fire detector’s principle of work diagram as shown in Figure 4.
At present, the light inductance smoke fire detector multi-uses bring the ordinary embedded microprocessor which A/D transforms, must complete the signal through the exterior electric circuit the enlargement and the filter handle work. In the product principle design process, needs to make the hardware parameter adjustment repeatedly to the exterior electric circuit; When PCB board wiring, must pay attention avoids electromagnetic interference from between spatial and component’s. May affirm that must solve these problems is very complex and the time-consuming work.
Election takes when detector’s microprocessors with the CY8C24223 chip (in dashed line frame is module function which in the PSoC chip has), with selected brings a/D function microprocessor to compare, has saved the massive exterior resources, like amplifier and related primary device, filter primary device and so on. The designers may in the PSoC equipment editor, complete the signal through the disposition analog module array and the digital module array to enlarge, the filter, the mold/number to transform, work and so on data storage, correspondence, and has avoided, because periphery components and so on amplifier in the PCB wiring time creates electromagnetic interference question. More importantly, the user may act according to the environment the change, like the daytime and the night, the pure space and the pollution space, the dynamic disposition amplifier’s gain factor, and realizes the multi-channel simulated signal input examination, cuts fire detector’s rate of false alarm.
In detector’s fast prototype project, through piece on systematic programmable composite signal array integrated application and dynamic disposition, raised the working efficiency enormously, caused the development cost to reduce the 1/2, PCB board level space to reduce l/3, the production cost reduced 1/10.
Conclusion
PSoC convenient, quick design contact surface, the object-oriented design development system, the composite signal array’s modulation and dynamic may dispose the function to enable it to have more nimble design way in the embedded system application, enables the designers to found the new system function at will. Using PSoC may fast, complete the corresponding procedure conveniently the development work, reduces product the research and development cycle, reduces the development cost and the production cost.
