Question about how to use INA and OUTA

KraZe_EyE

I understand that INA is a nibble that represents the current state of pins 0 - 3, and that OUTA will output on pins 0 - 3.

Can i use OUTA like this OUTA = 6 Store that in an outside memory chip
Then read it back from the memory test var = INA And get my 6 back as a binary 0110?

Do i have to put a binary number in OUTA? ie. OUTA = 0110

Basically for my final project I am trying to read data from an arithmatic logic unit(ALU) write it to memory, then read it later.
The address location and the read/write functionality is controlled by the stamp.

Here's the memory chip www.datasheet4u.com/share_search.php?sWord=TMS2114

And below is my program

Thanks for your help!

Post Edited (KraZe_EyE) : 11/12/2008 3:25:59 AM GMT

Carl Hayes

The hardware does not care how you represent the number -- binary, octal, hexadecimal, decimal, or other. It's still the same number. The compiler cares, but no matter whether you say 6, $6,%0110, or something else, the number is the same. It's like asking, will water still help my plants grow if instead of calling it "water", I instead say "Wasser" (German), "agua" (Spanish), or "eau" (French). The plants won't care what language you use, and neither will the electronic hardware.

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· -- Carl, nn5i

Mike Green

Just putting a value in OUTA will not write it to the memory. You have to activate the appropriate control lines (Chip Select and Write Enable). Similarly, you have to control the memory to read the data from a particular address, then you can use INA to sense the signal on the 4 data lines. You also have to use DIRA to select the direction (input or output) and do it so that the memory doesn't try to output data at the same time that the Stamp I/O pins are in output mode.

KraZe_EyE

So I can write a number using OUTA=6, and it will make the pins 0110. Using INA I can also store by using the command testvar=INA, correct?

I'm not sure what DIRA does; can I have a little example?


Thanks

Mike Green

Read the PBasic manual, particularly the section on Stamp architecture and memory organization. The direction register sets the direction of the I/O pins (input or output) and has the same divisions into bit groups as the input or output register.

KraZe_EyE

Okay I get the use of DIRs; but is this set in stone for the program? If i set an IO pin to an input can I change it later to and output?

Lab Rat

if the coding says input at a set time it is an input if later in the the program you say output on the pin i would imagine that it will then become an output
but i cant be 100% SURE only 99%
computers do this with a speacial chip but i forget what it was
it just lets datat from in one direction or the other via an internal switch
i have a few but i dont know where they are to get you the numbers

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Believe in it.

Post Edited (Lab Rat) : 11/12/2008 10:12:13 PM GMT

Mike Green

You can change an I/O pin at any time from input to output or from output to input by changing the contents of the corresponding DIR register bit.

KraZe_EyE

alright my project is working!!!!!!!!!!!!!!!!!!!!

thanks alot Mr. Green

I hope you guys can answer my n00b question cause this is the only thing holding project up.
I want to continously scan INA and display the result in a DEBUG statement, problem is I have the exit loop waiting for 'answer' to NOT = 0.
This screws it up because the stamp waits for me to input the 'answer' and therefore never refreshes the debug statement.

Any ideas? if this doesn;t make sense tell me and i'll try again


ReadWrite:

s1=1
s2=1
alu=0
PAUSE 10
DO
answer = 0
DEBUG CR,"Current ALU output is ", BIN5 INA, ", would you like to write ALU data to memory?",CR
DEBUG "0 for NO, 1 for YES",CR
DEBUGIN BIN1 answer
LOOP WHILE answer = 0

alu=1

IF answer = 1 THEN
GOTO careful
ELSE
GOTO main
ENDIF
RETURN