THIT K MODUL GHP NI VI IU KHIN 18F

THIT K MODULE GHP NI VI IU KHIN PIC18F4520VI TH NH MMC/SD LU TR TN HIU IN

Nguyn Vn n

Trng i hc Khoa hc, i hc Hu

Tm tt. Ni dung chnh ca bi bo tp trung vo vic thit k phn cng module ghp ni gia vi iu khin PIC18F4520 vi th nh MMC/SD, vit chng trnh phn mm np cho PIC18F4520 thc hin vic ghi mt s tn hiu in c hnh dng, tn s khc nhau v pht li tn hiu ban u. Cu trc phn cng v gii thut phn mm iu khin hot ng ca module do chng ti thit k, tnh ton v iu chnh p ng c yu cu t ra. Cc kt qu thc nghim cho thy module hot ng tt. C th tn hiu pht li ca module c hnh dng, mc in p nh v tn s gn trng vi tn hiu ngun pht, ph hp vi l thuyt tnh ton c t s mch thc nghim. Ngoi ra, kt qu cng th hin r c s ng b tt gia tc ghi v tc truy xut d liu cng nh kh nng lm vic hiu qu vi tn hiu vo tn s cao ca module. Kt qu ca bi bo ny l c s m rng trin khai hng ng dng trong thc tin nhm mc ch nng cao tnh linh ng trong cc h thng o v iu khin cc i lng vt l ni chung.1. t vn

Nghin cu vic thu v lu tr tn hiu in khng ch nhm mc ch p ng nhu cu gii tr ca con ngi m cn l tin lm nn tng cho vic nghin cu cng nh trin khai ng dng vo thc tin trong mt s lnh vc lin quan n vic thm d, o lng, iu khin cc i lng in v khng in.

S dng th nh MMC/SD ghi d liu l vn khng cn mi, tuy nhin can thip c vo vic x l v iu khin cc i lng o lin quan n tn hiu nhn c l vn rt ng quan tm. Ngoi cht lng k thut th gi thnh cng nh s linh ng cho tng ng dng c th ng vai tr khng nh i vi nhu cu s dng thc t.T vic nghin cu hot ng ca PIC18F4520 [7], DAC0808 [2], mt s mch in ng dng s dng vi mch OPAMP [1, 3], hot ng vo/ra d liu ch SPI ca th nh MMC/SD [5, 6] v phng thc giao tip gia PIC18F4520 vi MMC/SD [6], chng ti tin hnh thit k phn cng module ghp ni gia hai phn t chnh l PIC18F4520 v th nh MMC/SD cng nh vit chng trnh phn mm np cho PIC18F4520 module thc thi nhim v ghi tn hiu in vo MMC/SD v pht li tn hiu in ghi thng qua vic la chn t khi iu khin bn phm bn ngoi.Ngoi ra, vic kho st thc nghim qu trnh ghi/c ca module i vi mt s tn hiu in c hnh dng v tn s khc nhau cng c th hin r thng qua bi bo ny.2. Thc nghim

2.1. S khi ca module

Module c thit k theo s khi c gii hn bi ng ri nt hnh 1.

Hnh 1. S khi ca module

- Khi iu khin bn phm: gm cc phm nhn dng la chn, xc nhn ch ghi/c cho module v khi to li module.

- Mch lp u vo: ngoi vic cng thm mt mc in p mt chiu vo tn hiu tng t cn thu, khi ny cn c nhim v thc hin phi hp tr khng gia tr khng ra ca ngun tn hiu vi tr khng vo ca PIC18F4520.

- Khi hin th ghi/c: bo kt qu khi to th nh MMC/SD, hin th ch v trng thi hot ng ca module.

- Khi iu khin trung tm: y l trung tm iu khin hot ng cho module. Khi ny s dng phn t chnh l vi iu khin PIC18F4520 c np phn mm iu khin thc thi qu trnh ghi d liu vo th nh hoc truy xut d liu t th nh tng ng vi ch lm vic ca module. Vi qu trnh ghi, ADC ni ca PIC18F4520 c s dng chuyn i tn hiu tng t sau khi lp u vo thnh tn hiu s ghi vo khi lu tr d liu.

- Khi lu tr d liu: s dng th nh MMC/SD ghi d liu s c c.

- Khi chuyn i tn hiu D/A: s dng vi mch DAC0808 chuyn i tn hiu s sau khi truy xut t th nh thnh tn hiu tng t.

- Khi khuch i u ra: chuyn i tn hiu dng in t u ra ca DAC0808 thnh tn hiu in p trc khi a vo khi hin th tn hiu.2.2. Giao thc gia PIC18F4520 vi th nh MMC/SDGiao thc gia PIC18F4520 vi MMC/SD s dng trong bi bo c thit lp ch SPI. S chn v chc nng cc chn ca MMC/SD khi hot ng ch SPI c cho tng ng trn hnh 2 v bng 1 [5, 6].

Hnh 2. S chn ca MMC/SDGiao tip bt u c thc hin khi PIC18F4520 gi tn hiu thit lp mc thp cho chn CS ca MMC/SD, Chn CS lun gi mc thp trong qu trnh gi mt khung lnh cng nh qu trnh trao i d liu gia PIC18F4520 vi MMC/SD. Lnh c PIC18F4520 truyn n MMC/SD thng qua chn DI, phn hi lnh c MMC/SD gi ln PIC18F4520 qua chn DO, chn CLK l chn gi nhp gia PIC18F4520 vi MMC/SD. thc hin giao tip gia PIC18F4520 vi MMC/SD, u tin PIC18F4520 gi mt s lnh khi to v ci t cc thng s giao tip, sau cc khi d liu s lin tip c PIC18F4520 ghi vo MMC/SD hoc c t MMC/SD. Lnh t PIC18F4520 gi n MMC/SD c ng gi v sp xp trong mt khung nh dng gm 48 bit c chia thnh 6 byte vi cu trc c m t hnh 3. Gi tr v ngha ca cc bit c cho [5, 6].Khi nhn c mt khung lnh t PIC18F4520, MMC/SD s gi mt byte phn hi lnh. PIC18F4520 lin tc c byte phn hi ny cho n khi nhn c gi tr phn hi hp l. Tn hiu chn DI ca MMC/SD lun c gi mc cao trong qu trnh PIC18F4520 c byte phn hi.

Bi bo ny s dng byte phn hi R1 t MMC/SD vi khun dng cho hnh 4. Nu byte phn hi R1 c gi tr 00h, ngha l MMC/SD sn sng giao tip ghi/c ch SPI. Nu giao tip cha sn sng do li no , bit tng ng trong byte phn hi s c thit lp bng 1 [5, 6].Cc bc khi to MMC/SD hot ng ch SPI s dng trong bi bo:- Thit lp chn CS, DI ln mc cao.- Gi n MMC/SD 80 xung clock.

- Thit lp chn CS mc thp v gi lnh CDM0 gm 6 byte 40h, 00h, 00h, 00h, 00h, 95h t MMC/SD hot ng ch SPI.

- Kim tra byte phn hi R1. Nu byte R1 c gi tr 01h, lnh CMD0 thnh cng.

- Lp i lp li qu trnh gi lnh CMD1 v kim tra byte phn hi R1. Nu byte R1 c gi tr 00h, MMC/SD sn sng hot ng ghi/c. 2.3. Lc chng trnh np chip vi iu khinTrn c s s khi v giao thc SPI gia PIC18F4520 vi MMC/SD, chng ti thit k gii thut chng trnh np PIC18F4520 iu khin hot ng ca module theo lc cho hnh 5.Hnh 5. Lc chng trnh np PIC18F45203. Kt qu v tho lun

3.1. S mch nguyn l

T vic tm hiu v hot ng ca cc vi mch, th nh MMC/SD, mch lp v mch khuch i in p, chng ti thit k v lp rp hon chnh module vi s nguyn l c cho hnh 6a v hnh 6b.

Hnh 6a. Mch ghp ni u vo vi PIC18F4520, DAC0808 v khuch i u ra

Hnh 6b. Mch ghp ni gia khi iu khin bn phm vi PIC18F4520, MMC/SD v LCD3.2. Nguyn l hot ng v mt s c tnh ca module

Sau khi cp ngun cho module, khi iu khin trung tm s thc hin vic thit lp cc thanh ghi cho PIC18F4520 ng thi khi to th nh MMC/SD cho hot ng ch SPI thng qua mt s lnh gi t PIC18F4520, khi to giao tip gia vi iu khin PIC18F4520 vi th nh MMC/SD v i kt qu phn hi. Qu trnh khi to v kt qu phn hi c hin th trn mn hnh LCD. Nu khi to thnh cng, th nh sn sng thc hin vic giao tip, lc ny khi iu khin trung tm s i lnh iu khin t khi bn phm thc thi cc ch ghi/c tng ng.

- Ch ghi: khi iu khin trung tm pht tn hiu iu khin thc hin vic ghi d liu vo th nh MMC/SD. ch ny, tn hiu vo tng t sau khi c cng thm mt mc in p mt chiu t cp in tr phn p R1-R2 v qua b lp in p dng OPAMP TL082 s c a vo PIC18F4520 chuyn i thnh tn hiu s nh b chuyn i ADC ni 8 bit c thit lp trong PIC18F4520. Tn hiu s sau qu trnh chuyn i s c ghi vo th nh MMC/SD.

- Ch c: khi iu khin trung tm pht tn hiu iu khin thc hin vic c d liu t th nh MMC/SD. ch ny, khi iu khin trung tm s iu khin vic truy xut cc byte d liu t th nh MMC/SD chuyn n cc u ra ca PIC18F4520. Tn hiu s ra c a n cc u vo tng ng ca DAC0808 v qua b khuch i o dng OPAMP TL082 ly tn hiu in p ra tng t.

s hnh 6a, in p tng t Vi u vo module sau khi truyn qua C1 c cng thm mt mc in p mt chiu tr s VDC = 2,5V, tn hiu ny qua b lp in p s dng OPAMP TL082 a vo PIC18F4520 chuyn i sang tn hiu s thng qua b ADC ni ca PIC18F4520. V R6 = R7 = 2,2k(, DAC0808 v ADC ni c thit lp trong PIC18F4520 cng phn gii 8 bit, ngoi ra chng u c cp mc in p so snh +5V nn in p vo ADC (VADC) v in p pht li Vo ca module s bng nhau. Nh vy v mt l thuyt, module trn cho mc in p nh ca tn hiu pht ra Vo bng mc in p nh ca tn hiu u vo Vi.Nu ly mu vi tn s tha mn nh l Nyquist [4], in p ra Vo s cng dng vi in p vo Vi.

3.3. Kt qu thc thi ca module vi mt s tn hiu vo khc nhau

S dng dao ng k s DS-1250 o tn hiu ly mu, in p vo v in p pht li ca module, cc kt qu nhn c c dng nh hnh 7. Trong : Tn hiu in p vo o bi knh CH2 (di), tn hiu in p pht li o bi knh CH1 (trn).

3.4. Tho lun

Module s dng b chuyn i ADC ch 8 bit, vic ly mu tn hiu vo c thc hin bng phn mm iu khin np cho PIC18F4520. Vi module ny, mi chu k ly mu ta nhn c 1 byte d liu; sau 512 ln ly mu, 512 byte d liu s c ghi vo 1 sector ca MMC/SD, qu trnh ghi d liu vo MMC/SD lp i lp li theo chu trnh ni trn. T chui xung ly mu thu c hnh 7a, chng t qu trnh ly mu tn hiu ph hp vi nguyn l hot ng ca module ny. Tn s ly mu o c trn knh CH1 ca dao ng k kh cao, t khong 50kHz. Nh vy theo nh l ly mu Nyquist, module ny c kh nng hot ng vi tn hiu vo tn s cao ln ti 25kHz.T cc kt qu nhn c vi cc tn hiu vo khc nhau, ta thy rng tn hiu pht li ca module c hnh dng, mc in p nh v tn s gn trng vi tn hiu ngun pht, ngha l module chng ti thit k hot ng tt ph hp vi l thuyt tnh ton v c tnh ng b ghi/c cao.4. Kt lun

Kt qu bi bo chng t chng ti thit k v lp rp th nghim thnh cng module dng lu tr tn hiu in trn c s giao tip gia vi iu khin PIC18F4520 vi th nh MMC/SD. C th:

- hon thnh vic thit k v lp rp phn cng ca module.

- Vit hon chnh phn mm iu khin np cho chip vi iu khin PIC18F4520 thc hin vic ghi/c tn hiu in bng ngn ng MikroC Pro.

- kho st vic ghi/c mt vi tn hiu in c hnh dng v tn s khc nhau.Cc kt qu trn cho thy module hot ng tt. Trn c s module ny, chng ta hon ton c th m rng thm cc ng dng khc lin quan n vic ghi/c v x l tn hiu.TI LIU THAM KHO

[1]. Phm Minh H, K thut mch in t, Nh xut bn Khoa hc v k thut, H Ni, 2002.[2]. Ng Din Tp, o lng v iu khin bng my tnh, Nh xut bn Khoa hc v k thut, H Ni, 2004.[3]. Xun Th, K thut in t, Nh xut bn Gio dc, 1997.[4]. Nguyn Quc Trung, X l tn hiu v lc s, Nh xut bn Khoa hc v k thut, H Ni, 2004.[5]. Technical Documentation Group Hitachi Kodaira Semiconductor Co., Ltd., MultiMediaCardTM Users Manual, Website: http://www.dip8.ru/pdf/e603002a.pdf[6]. Dogan Ibrahim, SD Card Projects Using the PIC Microcontroller, Website: http://www.eetimes.com/ContentEETimes/Documents/1515_ch3.pdf[7]. Microchip Technology Inc., PIC18F2420/2520/4420/4520 Data Sheet 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology, Website: http://ww1.microchip.com/downloads/en/devicedoc/39631e.pdfDESIGNATION OF COUPLING MODULE BETWEEN

THE PIC18F4520 MICROCONTROLLER AND MMC/SD MEMORYTO STORE ELECTRICAL SIGNAL

Nguyen Van An

College of Sciences, Hue UniversitySummary. The main study of this report focuses on the design of the hardware module coupled between the PIC18F4520 microcontroller and MMC/SD memory, and writing software programs loaded for PIC18F4520 to make a recording of the electrical signals shape at various frequencies and play back the original signals. Hardware structure and software algorithm that control the action of module designed, calculated and adjusted by us, are suitable to the requirements. The experimental results show that the module works well. Specifically, the signals transmited from the module show the shape and peak of voltage and frequency nearly identical to the source signals, which is consistent with theoretical calculations from experimental circuit diagram. In addition, there is the good synchronization between the writen speed and the speed of data access, and the ability of the module to work effectively with high-frequency signals. The result of this work is the basis for expansion of practical applications in order to improve the flexibility of the system measurement and control of physical quantities in general.

Mch lp

u vo

Khi iu khin trung tm

Chuyn i D/A

Khi lu tr

d liu

Khuch i

u ra

My pht

tn hiu

Khi iu khin bn phm

Hin th ghi/c

Khi hin th tn hiu ra

Hnh 7b. Tn hiu vo xung vung 5kHz, 1Vpp

Y

N

Kt thc

Ngt giao tip

Hnh 4. Cu trc byte phn hi R1

Hnh 3. Cu trc khung lnh

Hnh 7h. Tn hiu vo xung tam gic 300Hz, 1Vpp

Hnh 7g. Tn hiu vo xung tam gic 1kHz, 1Vpp

Hnh 7f. Tn hiu vo iu ha 300Hz, 1Vpp

Hnh 7e. Tn hiu vo iu ha 1kHz, 1Vpp

Hnh 7d. Tn hiu vo xung vung 300Hz, 1Vpp

Hnh 7c. Tn hiu vo xung vung 1kHz, 1Vpp

Hnh 7a. Tn hiu ly mu

Y

N

N

Y

Y

N

N

Y

Kim tra nt nhn

Bng 1. Chc nng cc chn trong ch SPI

TT chnK hiuGhi ch1CSChn chn chip2DIVo d liu3Vss1Ni t4VccNi dng ngun5CLKChn gi nhp6Vss2Ni t7DORa d liu

Kim tra nt nhn

Ch Ghi/c

Mng 512 byte

Bt u

Kim tra phn hi MMC/SD

Tng Sector

Tng Sector

Ghi vo Sector

Xut mng 512 byte ra DAC

c Sector

Sector = 0

Ch c

c ADC

Sector = 0

Ch ghi

Thit lp

SPI, ADC, LCD

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