Power suppy 8051 Max current Limit

[Jeffrey Peter]

If I am using a 5V supply to MC do I have monitor the current input to Vdd. If so how ?
Thanks in advance..

 

[tpetar]

You should pay attention on data given in manufacturer dadasheet of particulat uC for total max current and max current per each pin. You dont need to measure, you can just make simple calculation of current, but if you not sure then you can measure with ampermeter.

 

[bhav]

51 cann sink a good amount of current

 

[tpetar]

8051 is family of uC, better specify what uC exactly is in foxus ?

If you mean on 89S51 & 89S52 :

Maximum IOL per port pin: 10 mA
Maximum IOL per 8-bit port: Port 0 - 26 mA Ports 1, 2, 3 - 15 mA
Maximum total IOL for all output pins: 71 mA


89C2051 :

Maximum IOL per port pin: 20 mA
Maximum total IOL for all output pins: 80 mA

 

[Jeffrey Peter]

8051 is family of uC, better specify what uC exactly is in foxus ?

I'm going to use 89S52... so I'm wondering if I could directly connect a 5v DC across its Vcc and Gnd

 

[Robin Khosla]

You don't need to monitor the voltage
1st step will be to make the power supply and check by multimeter that at the output u r getting 5V then proceed further

when u complete ur hardware then u need to check the vcc and ground at each vcc point of the circuit
e.g. 40pin of controller
1st pin in case of lcd etc....

 

[tpetar]

I'm going to use 89S52... so I'm wondering if I could directly connect a 5v DC across its Vcc and Gnd

Yes you can connect 5V on 89S52 pins, and you should use 100nF on uC VDD,VSS pins. Dont use bad power supply. You can make easy one with 7805 regulator and few capacitors.

 

[Robin Khosla]

if you want to use 5v battery

then simply check the voltage of the battery to be 5v
and can simply use it in your circuit

 

[malleswari]

IDD power supply current:

active mode @ 12 MHz - 11.5 mA
@ 40 MHz - 50 mA
idle mode @ 12 MHz - 8.5 mA
@ 40 MHz - 42 mA

 

[Robin Khosla]

1. If you want to use 5V battery then simply check the voltage of the battery to be 5v using multimeter.
2. Usually, you will get a 9V battery from market. use that battery and after this connect an 7805 IC to regulate it to 5V.

but don't forget to use a voltage regulator 7805 in either case.

i.e. Battery ---------- Voltage regulator 7805 ------------- your circuit