8 Threads found on edaboard.com: Read Address From 8051
hi,all i face problem in my program of 8051 mcu with the following restrictions :1-my program must start at address 2000h(2 byte)
2-dptr register used for other purposes so,i cant use it to point to the memory address
my program include mov dptr,#porta
movx a,@dptr ;read digital data (...)
Microcontrollers :: 04-01-2013 19:55 :: anasfuad33eng :: Replies: 0 :: Views: 387
so ive been putting together a 8031/8051 system on a breadboard with external PROM and going to be using external RAM, i can write to an External Memory address (by way of latch) and display the value on 8 LEDs no problem, the problem i have is i want to read an 8 bit value from a memory (...)
Microcontrollers :: 08-10-2012 20:33 :: 3BABY :: Replies: 8 :: Views: 804
I have integrated a MFRC500 reader IC with a p89v51rd2 uC. I have used Multiplexed address/data lines with separate read and write strobe configuration.I am just thinking of testing the working of the parallel connection by just reading a register from the MFRC. The MFRC contains the product (...)
Microcontrollers :: 04-19-2012 10:39 :: Ram Prasadh :: Replies: 0 :: Views: 592
There is no way to read the value of PC (internal Program Memory) ..
But, if you, for example, trigger an interrupt you can read (within interrupt routine) the very first two byes from the Stack - they will be PCH and PCL ..
This would be like asking: What address are you about to execute next (after returning (...)
Microcontrollers :: 08-07-2007 08:28 :: IanP :: Replies: 3 :: Views: 3027
There is no way you can "assert" PSEN in program ..
If you want to read external program memory starting from address 0000h you have to wire /EA to 0V ..
If /EA is connected to +5V 80C51 will read internal program memory (0000h-0FFFh) and whenever the program counter (PC) contains a number that is larger than 0FFFh it (...)
Microcontrollers :: 01-30-2007 00:05 :: IanP :: Replies: 4 :: Views: 2523
You can program 8051 to act as 8255 PIA ..
To control 8255 you need 11 lines: /RD, /WR/ A0, A1 and D0-D7 ..
All what you have to do is to program 8051 to read from (or to write to) multiplexed address/data bus .. if you know how it works it shouldn't be difficuit ..
Once you have this, take commands used (...)
Microcontrollers :: 01-22-2007 06:44 :: IanP :: Replies: 2 :: Views: 1804
To connect this memory to 8051 microcontroler you need 8-bitt address latch on A/D0, .., A/D7 (74373) .. Do you have it?
The CE1 pin can be connected to 0V, CE2 to +5V, OE to ?C RD and WR to ?C WR ..
Once you have all the above connction in place you can use MOVX instructions to read data from and write data to this (...)
Microcontrollers :: 11-24-2006 04:57 :: IanP :: Replies: 5 :: Views: 1026
Which addresses are you talking about: A0 and A1?
They are generated by the system microcontroller and, in systems based on 8051 or 8085, for example, which use multiplexed address/data bus, they are latched in the address latch just before microcontroller attempts to read from or to (...)
Microcontrollers :: 08-11-2006 09:32 :: IanP :: Replies: 5 :: Views: 3123