8051 microcontoller

[3loah]

this my first participation in the forum so hello everybody i would like to help me on my homework .the question is how to connect 8 different devices to 8051 micro-controller my teacher used latch and decoder to minimize the ports that used for addressing the devices could anyone tell me how i can do it .

 

[Ian Rogers]

The 138 decoder can support 8 addresses ... What are YOUR ideas.... Eprom, Ram, LCD, ADC, DAC, Bus expander, UART and ??

You'll need the 373 to latch the multiplexed A/D bus... Try and jot something down and I'll take a look at it..

 

[3loah]

so can i use tow of 138 to address let say 7 smegma and LCD and i did not get the whole idea during the classes about latching the the port po-p7 because could u please give a brief explanation thanks

 

[Ian Rogers]

You need ONE 138 decoder... This little device can switch up to 8 external devices at addresses 0x8000, 0xC000, 0xE000, 0xA000, 0x6000, 0x4000, 0x2000 and 0x0000

You use A15,A14 and A13 to communicate with all the external devices

 

[WTP Pepper]

A drawing that doesn't need a Rosetta Stone to decipher would help.