Page 26 - PIC18F4550微處理機C語言設計實務

PIC18F4550 ฆஈଣዚ C ႧԊணࠇྼਕ

˸ char މԷd1 ࡈ Byte މ 8 ࡈ bit€bit7ä0d͜ signed ܁ѓٙᜊᅰۨ࿒މϞ੭
͍ࠋୌ໮ᅰd˸ bit7 މୌ໮ЗʩiϾ unsigned މʔ੭ୌ໮ᅰf

signed char ̙ڌͪᇍఖމ –128ä127dunsigned char ᇍఖމ 0ä255fᔊఊԸႭd

߰ࠅπ׳ࠋᅰٙᅰ࠽ఱࠅਗ਼ᜊᅰ܁ѓϓϞ໮ᅰd˲̀඲Ͻᅇᜊᅰڗܓ݊щԑ੄π׳༈
ᅰ࠽f

ίᅠᄳ C ႧԊٙࣛࡉdৰə೻όᇁึЦ͜Ց೻όাኳ᜗€PIC ʫ௅ٙ Program
memoryʘ̮dɰ̀඲ࠅԴ͜ՑᜊᅰdϾவԬᜊᅰ݊׳ໄί PIC ʫ௅ٙ RAMdί೻

όٙੂБཀ೻ʕdᜊᅰٙʫ࢙ึʔᓙٙᜊʷdШ݊ί೻όԴ͜ʘۃɓ֛ࠅԫ΋̋˸܁
ѓdᜫᇜᙇኜٝ༸הԴٙ͜ӊɓࡈᜊᅰٙɽʃdԨ˲މӊɓࡈᜊᅰʱৣাኳ᜗€RAM
Зѧf܁ѓᜊᅰٙႧجνɨj

ᜊᅰۨ࿒ ᜊᅰΤ၈ ;

Էνj

char var1; // ܁ѓᜊᅰ var1dᜊᅰۨ࿒݊οʩ
unsigned int var2; // ܁ѓᜊᅰ var2dᜊᅰۨ࿒݊ೌୌ໮዆ᅰ

܁ѓᜊᅰٙࣛࡉɓ֛ࠅϽඎՑӊɓࡈᜊᅰί೻όʘʕԴ̙ࣛ͜ঐٙ௰ʃ࠽ձ௰ɽ

࠽d್ܝΎ፯኿͍ᆽٙᜊᅰۨ࿒̋˸܁ѓd߰፯኿፹ႬdϞ̙ঐί೻ό༶Ъʕପ͛ɓ
Ԭࠇၑ፹ႬdவԨʔ݊ᇜᙇኜ̙˸кᓙ̈Ըd̀඲ࠅ೻όᅠᄳٙɛІʊءจf

Էνj

unsigned char var1,var2,var3;
var1 = 100;
var2 = 200;
var3 = var1+var2;

੽ɪࠦٙԷɿ̙˸޶Ցdɓක֐܁ѓəɧࡈᜊᅰ var1evar2evar3 ே݊ unsigned

chardה˸ɧࡈᜊᅰٙ௰ɽ࠽ே݊ 255dvar1 ၾ var2 ٙڋ֐࠽ɓࡈ݊ 100 ̤ɓࡈ݊
200dே݊ୌΥ unsigned char ٙ࠽ɽ࠽dШ݊௰ܝҪ var1+var2 ٙ࠽׳ɝ var3 ఱึ೯͛
ਪᕚdί೻ό༶ၑɪҎૐ var3 ݊ var1 ၾ var2 ٙ̋ᐼ࠽މ 300dШ݊ var3 ٙ௰ɽ࠽̥

ঐ݊ 255dה˸௰ܝ var3 ٙഐ؈ึᜊϓ݊ 44dΪމ൴ཀ 255 ٙ௅ʱਗ਼ึආЗՑɨɓࡈ
Byted̥वɨ௵ቱٙ௅ʱf

300 - 256=44

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