Logic level:
Logic level ni nini?
Logic level ni kiwango maalumu cha voltage au kiasi maalumu cha voltage signal/ mawimbi ya umeme.
Logic level ndo hupelekea kompyuta au mfumo wowote wa kidigital/digital circuit kutambua kwamba hii signal/mawimbi ni binary 0 au binary 1,...ni LOW(0) au high(1),..OFF au ON...wale wazee wa Arduino na microcontroller kwa ujumla wanajua HIGH na LOW zinavyotumika in both hardware and software realm.
Logic 0 or Logic 1
Why name Logic? It comes from Logic gates, the guys that engineers binary 0 and binary 1 and hence digital electronics as a whole. Logic gates/ sorts of NANDs, ANDs, NOTs, etc.
Ukiachana na electronics ya ki-analogia, electronics ya ki-digitali inatumia Binary logic (0 and 1) katika ku store, process na kutransmit data au information. Binary 1 pia inaitwa HIGH signal na binary 0 pia inaitwa LOW signal.
Ni kwamba voltage signal ikipita kwenye digital circuit inakua na kiwango flani cha voltage ambacho kimewekwa na manufacture kwa kufuata principle za electronics kitambuliwe kama ni HIGH(1) au LOW(0), kwahiyo computer haitajua hii signal ina voltage kiasi gani, yenyewe itajua hii signal ni 1 au 0.
Je binary 1 na binary 0 zinatambulika vipi na kifaa cha electronics ya kidigitali?
Logic families: ICs za kidigitali zinatengenezwa kwa kufuata muundo/circuit configuration mojawapo na technology inayotumika.
Logic families ni aina mbalimbali za mpangilio wa circuit za transistor katika logic gate ili zitoe output.
Logic family moja na nyinginezo zote zina rely katika 1 or 0, tofauti yake ni muundo wa circuit zao na technolojia iliotumika kuzitengezeneza.
Nini tofauti ya Logic family moja na nyingine?
Logic family ina define ‘electrical characteristics’ flani ambazo zina ibound na family nyingine. Katika logic family moja kunaweza kua na subfamily na/au series/matoleo kadhaa kulingana na technological changes.
Mfano: iPhone Family: iPhone 5, 6,...
Samsung family: A9, A10,...
Electrical characteristics zinazotengeneza family zinategemea na;
1. supply voltage range, IC inatumia voltage kiasi gani kama power supply/ya kukifanya kiwe ON/active na sio voltage level.
2. Speed of response, IC chip inafanya kazi kwa spidi kiasi gani?
3. power dissipation, kiasi gani cha nishati IC inaweza kupoteza
4. Input and output logic levels, IC inaweza kutoa au kupokea voltage kiasi gani ili itambulike kama 1 au 0? ( hapa ndo IC ‘huzaa’ binary 1 na binary 0)
5. current sourcing and sinking capability, uwezo wa kutoa na kupokea umeme
6. fan-out, IC output capability
7. noise margin, uwezo wa kuhimili signal unwanted/impurity voltage signals
8. etc.
Aina za Logic families:
IC nyingi za kidigtali hutengenezwa na moja kati ya bipolar devices au MOS devices au vyote kwa pamoja.
Families that use bipolar devices: (also bipolar families):
1. diode logic (DL)
2. resistor transistor logic (RTL)
3. diode transistor logic (DTL)
4. transistor transistor logic (TTL)
5. emitter coupled logic (ECL) also known as current mode logic (CML), and
6. integrated injection logic (𝐼 2L)
Families that use MOS devices:
MOS=Metal-Oxide-Semiconductor (metal? e,g copper)
1. PMOS family (using P-channel MOSFETs)
2. NMOS family (using N-channel MOSFETs) and
3. CMOS family (using both N- and P-channel devices)
Families that use both Bipolar and MOS families are Bi-MOS families.
Katika families za hapo juu, nyingi zimebaki kama history tu na hazikuweza kuwa implemented wala kutengeneza ICs. Nyingine zilikuwa na drawbacks kubwa sana katika real digital IC implementation.
Logic families ambazo zinatumika kw asana kutengeneza digital ICs ni TTL, CMOS, ECL, NMOS and Bi-CMOS. NMOS hutumika katika LSI na VLSI (yaani microprocessors na other chips).
Among ya hizo families zilizobakia, TTL na CMOS ndo zinazotumika kwa sana ku implement ICs ili ku implement logic functions.
Making long story short:
Ukiachana na working principle, all the electronics and physics behind ya TTL family na CMOS family lets jump to TTL and CMOS logic levels.
5V TTL logic levels
Digital system nyingi tunazotumia zinatumia 3.3v au 5v TTL levels. TTL imeundwa na bipolar transistor ambazo zinaweza kuleta logic states yaani 1 na 0.
Katika 5V TTL level standard, je binary 1 na binary 0 zinatokeaje?
5V TTL standard voltage levels:
IC au TTL device inakua powered na 5V ambayo huitwa Vcc au common-collector voltage
Upande wa kutoa/output:
Ili signal itambulike kama binary 1 au logic state HIGH ikiwa inatoka kweye TTL logic device au IC inabidi isiwe chini ya 2.7V au isiwe juu ya 5V. yaani icheze kati ya 2.7V na 5V ndo inakua HIGH(1).Ili signal itambulike kama binary 0 au logic state LOW ikiwa inatoka kweye TTL device au IC inabidi isiwe chini ya 0V au isivuke juu ya 0.4V. yaani icheze kati ya 0V na 0.4V ndo itakuwa
LOW(0).
Yaani 0 na 1 kwenye binary system, digital na computer ni hamna kitu bali ni circuit ambayo inasubiri siginal ipite harafu ipime kiasi cha voltage na iweke 1 au 0.
Output signal:
0V mpaka 0.4V ni binary 0 au LOW
2.7V mpaka 5V ni binary 1 au HIGH
Je vipi signal ikiwa kati ya 0.4V mpaka 2.7V? hii range ni undefined, italeta invalid states, kitaalamu inaitwa floating voltage.
Wale wa miprcoprocessor na microcontroller programing wanakutanaga na everything is ok and active but it doesn’t work, probably I/O pin zio katika floating au invalid states yaani siyo HIGH wala LOW kwahiyo hata microprocessor/microcontroller inashindwa ifanye nini na haiwezi kutatua hilo tatizo ni wewe tu kuhakikisha voltage sahihi kwa kufuta manufacturer datasheet.
Upande wa kupokea/input:
TTL device ikipokea signal ya voltage 0V mpaka 0.8V basi hii hutambulika kama LOW(0). Na ikiwa imepokea signal ya voltage 2V mpaka 5V basi hii hua HIGH(1)
Tena je what if signal ya 0.8V mpaka 2V range? Pia ni invalid states, undefined, no output.
TTL device interfaces: USB ports zinatumia TTL logic e.g zile computer ports, flash drive ports, mobile chargers ports for data transmission, etc they use 5V TTL standard. And so many interfaces and devices.
3.3V CMOS levels:
Kutokana na kukua kwa teknolojia, basi kuna vifaa vinavyotumia umeme kiasi kidogo sana vimetengenezwa kutoka 5V TTL logic mpaka 3.3V CMOS logic, pia hupunguza costs za IC na fabrication ya overall digital circuit systems.
Katika CMOS INPUT SIGNAL: 2V mpaka 3.3V ni HIGH(1) 0V mpaka 0.8V ni LOW(0)
OUTPUT SIGNAL: 2.4V MPAKA 3.3V ni HIGH(1) 0V mpaka 0.5V ni LOW(0). Pia hata CMOS kuna invalid states.
What if unataka ku interface TTL na CMOS devices? Kuna device inaitwa logic level converter au logiclevel shifter, it does all the work au manually na resistors potential divider kutoka 5V logic kwenda 3.3V logic. e.g kuinterface GPS sensor ya 3.3V (CMOS) na 5V microprocessor I/O pin (TTL)
and son..
So computer and other digital systems understands 1 and 0, more like logic gates maintaining voltage standards than reality and hence implementing logic functions.
NOTE: This is layman explanation in order to understand how the microelectronic instrumentation and measurement works.
Regards,
An Engineer.
Logic level ni nini?
Logic level ni kiwango maalumu cha voltage au kiasi maalumu cha voltage signal/ mawimbi ya umeme.
Logic level ndo hupelekea kompyuta au mfumo wowote wa kidigital/digital circuit kutambua kwamba hii signal/mawimbi ni binary 0 au binary 1,...ni LOW(0) au high(1),..OFF au ON...wale wazee wa Arduino na microcontroller kwa ujumla wanajua HIGH na LOW zinavyotumika in both hardware and software realm.
Logic 0 or Logic 1
Why name Logic? It comes from Logic gates, the guys that engineers binary 0 and binary 1 and hence digital electronics as a whole. Logic gates/ sorts of NANDs, ANDs, NOTs, etc.
Ukiachana na electronics ya ki-analogia, electronics ya ki-digitali inatumia Binary logic (0 and 1) katika ku store, process na kutransmit data au information. Binary 1 pia inaitwa HIGH signal na binary 0 pia inaitwa LOW signal.
Ni kwamba voltage signal ikipita kwenye digital circuit inakua na kiwango flani cha voltage ambacho kimewekwa na manufacture kwa kufuata principle za electronics kitambuliwe kama ni HIGH(1) au LOW(0), kwahiyo computer haitajua hii signal ina voltage kiasi gani, yenyewe itajua hii signal ni 1 au 0.
Je binary 1 na binary 0 zinatambulika vipi na kifaa cha electronics ya kidigitali?
Logic families: ICs za kidigitali zinatengenezwa kwa kufuata muundo/circuit configuration mojawapo na technology inayotumika.
Logic families ni aina mbalimbali za mpangilio wa circuit za transistor katika logic gate ili zitoe output.
Logic family moja na nyinginezo zote zina rely katika 1 or 0, tofauti yake ni muundo wa circuit zao na technolojia iliotumika kuzitengezeneza.
Nini tofauti ya Logic family moja na nyingine?
Logic family ina define ‘electrical characteristics’ flani ambazo zina ibound na family nyingine. Katika logic family moja kunaweza kua na subfamily na/au series/matoleo kadhaa kulingana na technological changes.
Mfano: iPhone Family: iPhone 5, 6,...
Samsung family: A9, A10,...
Electrical characteristics zinazotengeneza family zinategemea na;
1. supply voltage range, IC inatumia voltage kiasi gani kama power supply/ya kukifanya kiwe ON/active na sio voltage level.
2. Speed of response, IC chip inafanya kazi kwa spidi kiasi gani?
3. power dissipation, kiasi gani cha nishati IC inaweza kupoteza
4. Input and output logic levels, IC inaweza kutoa au kupokea voltage kiasi gani ili itambulike kama 1 au 0? ( hapa ndo IC ‘huzaa’ binary 1 na binary 0)
5. current sourcing and sinking capability, uwezo wa kutoa na kupokea umeme
6. fan-out, IC output capability
7. noise margin, uwezo wa kuhimili signal unwanted/impurity voltage signals
8. etc.
Aina za Logic families:
IC nyingi za kidigtali hutengenezwa na moja kati ya bipolar devices au MOS devices au vyote kwa pamoja.
Families that use bipolar devices: (also bipolar families):
1. diode logic (DL)
2. resistor transistor logic (RTL)
3. diode transistor logic (DTL)
4. transistor transistor logic (TTL)
5. emitter coupled logic (ECL) also known as current mode logic (CML), and
6. integrated injection logic (𝐼 2L)
Families that use MOS devices:
MOS=Metal-Oxide-Semiconductor (metal? e,g copper)
1. PMOS family (using P-channel MOSFETs)
2. NMOS family (using N-channel MOSFETs) and
3. CMOS family (using both N- and P-channel devices)
Families that use both Bipolar and MOS families are Bi-MOS families.
Katika families za hapo juu, nyingi zimebaki kama history tu na hazikuweza kuwa implemented wala kutengeneza ICs. Nyingine zilikuwa na drawbacks kubwa sana katika real digital IC implementation.
Logic families ambazo zinatumika kw asana kutengeneza digital ICs ni TTL, CMOS, ECL, NMOS and Bi-CMOS. NMOS hutumika katika LSI na VLSI (yaani microprocessors na other chips).
Among ya hizo families zilizobakia, TTL na CMOS ndo zinazotumika kwa sana ku implement ICs ili ku implement logic functions.
Making long story short:
Ukiachana na working principle, all the electronics and physics behind ya TTL family na CMOS family lets jump to TTL and CMOS logic levels.
5V TTL logic levels
Digital system nyingi tunazotumia zinatumia 3.3v au 5v TTL levels. TTL imeundwa na bipolar transistor ambazo zinaweza kuleta logic states yaani 1 na 0.
Katika 5V TTL level standard, je binary 1 na binary 0 zinatokeaje?
5V TTL standard voltage levels:
IC au TTL device inakua powered na 5V ambayo huitwa Vcc au common-collector voltage
Upande wa kutoa/output:
Ili signal itambulike kama binary 1 au logic state HIGH ikiwa inatoka kweye TTL logic device au IC inabidi isiwe chini ya 2.7V au isiwe juu ya 5V. yaani icheze kati ya 2.7V na 5V ndo inakua HIGH(1).Ili signal itambulike kama binary 0 au logic state LOW ikiwa inatoka kweye TTL device au IC inabidi isiwe chini ya 0V au isivuke juu ya 0.4V. yaani icheze kati ya 0V na 0.4V ndo itakuwa
LOW(0).
Yaani 0 na 1 kwenye binary system, digital na computer ni hamna kitu bali ni circuit ambayo inasubiri siginal ipite harafu ipime kiasi cha voltage na iweke 1 au 0.
Output signal:
0V mpaka 0.4V ni binary 0 au LOW
2.7V mpaka 5V ni binary 1 au HIGH
Je vipi signal ikiwa kati ya 0.4V mpaka 2.7V? hii range ni undefined, italeta invalid states, kitaalamu inaitwa floating voltage.
Wale wa miprcoprocessor na microcontroller programing wanakutanaga na everything is ok and active but it doesn’t work, probably I/O pin zio katika floating au invalid states yaani siyo HIGH wala LOW kwahiyo hata microprocessor/microcontroller inashindwa ifanye nini na haiwezi kutatua hilo tatizo ni wewe tu kuhakikisha voltage sahihi kwa kufuta manufacturer datasheet.
Upande wa kupokea/input:
TTL device ikipokea signal ya voltage 0V mpaka 0.8V basi hii hutambulika kama LOW(0). Na ikiwa imepokea signal ya voltage 2V mpaka 5V basi hii hua HIGH(1)
Tena je what if signal ya 0.8V mpaka 2V range? Pia ni invalid states, undefined, no output.
TTL device interfaces: USB ports zinatumia TTL logic e.g zile computer ports, flash drive ports, mobile chargers ports for data transmission, etc they use 5V TTL standard. And so many interfaces and devices.
3.3V CMOS levels:
Kutokana na kukua kwa teknolojia, basi kuna vifaa vinavyotumia umeme kiasi kidogo sana vimetengenezwa kutoka 5V TTL logic mpaka 3.3V CMOS logic, pia hupunguza costs za IC na fabrication ya overall digital circuit systems.
Katika CMOS INPUT SIGNAL: 2V mpaka 3.3V ni HIGH(1) 0V mpaka 0.8V ni LOW(0)
OUTPUT SIGNAL: 2.4V MPAKA 3.3V ni HIGH(1) 0V mpaka 0.5V ni LOW(0). Pia hata CMOS kuna invalid states.
What if unataka ku interface TTL na CMOS devices? Kuna device inaitwa logic level converter au logiclevel shifter, it does all the work au manually na resistors potential divider kutoka 5V logic kwenda 3.3V logic. e.g kuinterface GPS sensor ya 3.3V (CMOS) na 5V microprocessor I/O pin (TTL)
and son..
So computer and other digital systems understands 1 and 0, more like logic gates maintaining voltage standards than reality and hence implementing logic functions.
NOTE: This is layman explanation in order to understand how the microelectronic instrumentation and measurement works.
Regards,
An Engineer.
