reducing shiftout clock freq and PS2/PC interfacing ....

[iugmoh]

Hi all , I have some experience with PS/2 and PIC since I made interfacing between keyboard or barcode reader PS/2 and PIC microcontrollers, you may take these considrations in your work:

1) PS/2 have two signals to communicate with it , clock and data
2) clock generated and data sends at every falling edge of the clock
3) each character represented with 33 bits ( make code , break code , make code)
4) each 11 bits is consist of ( 1 start bit , 8 data bits , 1 parity bit , 1 stop bit)
5) low level of clock duration is about 50 microsecond

you can search on google for PS/2 keyboard interface for more specification

I don't know the way how you use optical wireless but if you attach the schematic will be better

[wireless magic]

hello iugmoh

thanks GOD to find someone to help

ok lets see from your points what I might have a problem with is points : 2,5

2) clock generated and data sends at every falling edge of the clock

ok I read this befor in a document some where but the question is how can this point implemented is there any speacial instruction that can make an affect on the clock generated from shiftout instruction ?

OR

does the shiftout already takes this point in the consideration ??!! oh boy this one !

5) low level of clock duration is about 50 microsecond

hmmm there I think it can be between 30 - 50 us but the problem how can I achive this if I use an osc = 4MHz and shiftout gives freq of clock = 50kHz

which means low level of clock duration is about 10 microsecond , true ?!!

so how did you solve those problems ? ( using the PICBasic )

or should I use other IC's to help me in !!

thanks and waiting for your replay and to see your experiance on that.

thanks again

[sayzer]

I am sure this link is somewhere in this forum.

http://www.computer-engineering.org/ps2protocol/

[wireless magic]

hello sayzer

actually I know this protocolle befor the problem how can I emplement it and make an "A"
appears on the notepad or microsoftword using pic 16f877A

I used shiftout ...., ..... , 5 [% 010100110/11]

but it not working how can I control the clock frequency I want it between 10 - 16.7 KHz !

please give me some help.

[sayzer]

May be it would be much better if you write your own routine.

You can control Clock and Data lines with more accuracy and thus play with Clock frequency as you like.

Example:

<font color="#000000">        
        Temp = <font color="#FF0000"><b>$15      </b></font><font color="#000080"><i>' Send &quot;q&quot; as an example.
        
        </i></font>DatTime = <font color="#FF0000"><b>10    </b></font><font color="#000080"><i>' Data Pause Time.
        </i></font>ClkTime = <font color="#FF0000"><b>50    </b></font><font color="#000080"><i>' Clock Pause time.
        
        </i><b>OUTPUT </b></font>TxCLK    <font color="#000080"><i>' Before you send anything, assign the pins as output pins.
        </i><b>OUTPUT </b></font>TxDAT

        TxCLK = <font color="#FF0000"><b>1
        </b></font><font color="#000080"><b>PAUSEUS </b></font>DatTime
        TxDAT = STARTBit      <font color="#000080"><i>' Start bit is always zero.
        </i><b>PAUSEUS </b></font>DatTime        
        TxCLK = <font color="#FF0000"><b>0
        </b></font><font color="#000080"><b>PAUSEUS </b></font>ClkTime

        TxCLK = <font color="#FF0000"><b>1
        </b></font><font color="#000080"><b>PAUSEUS </b></font>DatTime
        TxDAT = Temp.<font color="#FF0000"><b>0        </b></font><font color="#000080"><i>' Bit 0.
        </i><b>PAUSEUS </b></font>DatTime        
        TxCLK = <font color="#FF0000"><b>0
        </b></font><font color="#000080"><b>PAUSEUS </b></font>ClkTime


        TxCLK = <font color="#FF0000"><b>1
        </b></font><font color="#000080"><b>PAUSEUS </b></font>DatTime
        TxDAT = Temp.<font color="#FF0000"><b>1        </b></font><font color="#000080"><i>' Bit 1.
        </i><b>PAUSEUS </b></font>DatTime        
        TxCLK = <font color="#FF0000"><b>0
        </b></font><font color="#000080"><b>PAUSEUS </b></font>ClkTime

    
        TxCLK = <font color="#FF0000"><b>1
        </b></font><font color="#000080"><b>PAUSEUS </b></font>DatTime
        TxDAT = Temp.<font color="#FF0000"><b>2        </b></font><font color="#000080"><i>' Bit 2.
        </i><b>PAUSEUS </b></font>DatTime        
        TxCLK = <font color="#FF0000"><b>0
        </b></font><font color="#000080"><b>PAUSEUS </b></font>ClkTime

    
        TxCLK = <font color="#FF0000"><b>1
        </b></font><font color="#000080"><b>PAUSEUS </b></font>DatTime
        TxDAT = Temp.<font color="#FF0000"><b>3        </b></font><font color="#000080"><i>' Bit 3.
        </i><b>PAUSEUS </b></font>DatTime        
        TxCLK = <font color="#FF0000"><b>0
        </b></font><font color="#000080"><b>PAUSEUS </b></font>ClkTime

    
        TxCLK = <font color="#FF0000"><b>1
        </b></font><font color="#000080"><b>PAUSEUS </b></font>DatTime
        TxDAT = Temp.<font color="#FF0000"><b>4        </b></font><font color="#000080"><i>' Bit 4.
        </i><b>PAUSEUS </b></font>DatTime        
        TxCLK = <font color="#FF0000"><b>0
        </b></font><font color="#000080"><b>PAUSEUS </b></font>ClkTime

    
        TxCLK = <font color="#FF0000"><b>1
        </b></font><font color="#000080"><b>PAUSEUS </b></font>DatTime
        TxDAT = Temp.<font color="#FF0000"><b>5        </b></font><font color="#000080"><i>' Bit 5.
        </i><b>PAUSEUS </b></font>DatTime        
        TxCLK = <font color="#FF0000"><b>0
        </b></font><font color="#000080"><b>PAUSEUS </b></font>ClkTime

    
        TxCLK = <font color="#FF0000"><b>1
        </b></font><font color="#000080"><b>PAUSEUS </b></font>DatTime        
        TxDAT = Temp.<font color="#FF0000"><b>6        </b></font><font color="#000080"><i>' Bit 6.
        </i><b>PAUSEUS </b></font>DatTime        
        TxCLK = <font color="#FF0000"><b>0
        </b></font><font color="#000080"><b>PAUSEUS </b></font>ClkTime

    
        TxCLK = <font color="#FF0000"><b>1
        </b></font><font color="#000080"><b>PAUSEUS </b></font>DatTime        
        TxDAT = Temp.<font color="#FF0000"><b>7        </b></font><font color="#000080"><i>' Bit 7.
        </i><b>PAUSEUS </b></font>DatTime        
        TxCLK = <font color="#FF0000"><b>0
        </b></font><font color="#000080"><b>PAUSEUS </b></font>ClkTime

    
        TxCLK = <font color="#FF0000"><b>1
        </b></font><font color="#000080"><b>PAUSEUS </b></font>DatTime        
        TxDAT = Parity        <font color="#000080"><i>' Parity Bit.
        </i><b>PAUSEUS </b></font>DatTime       <font color="#000080"><i>' You must calculate Parity bit_ 
        </i></font>TxCLK = <font color="#FF0000"><b>0               </b></font><font color="#000080"><i>'in somewhere before putting it here. 
        </i><b>PAUSEUS </b></font>ClkTime

    
        TxCLK = <font color="#FF0000"><b>1
        </b></font><font color="#000080"><b>PAUSEUS </b></font>DatTime        
        TxDAT = StopBit       <font color="#000080"><i>' Stop bit is always 1. 
        </i><b>PAUSEUS </b></font>DatTime           <font color="#000080"><i>' Have a variable named StopBit and make it 1.
        </i></font>TxCLK = <font color="#FF0000"><b>0
        </b></font><font color="#000080"><b>PAUSEUS </b></font>ClkTime
        
        <font color="#000080"><b>INPUT </b></font>TxCLK           <font color="#000080"><i>' when you are done with sending a byte, 
        </i><b>INPUT </b></font>TxDAT              <font color="#000080"><i>'assign the pins as input pins.

    
</i></font>

This routine works fine.
But I am having issues with different computers.
Thus, you will have to play with Data and Clock pauses.
Also, you will have to have a Delay between each "SEND".

[wireless magic]

ok actually I tried your code with little midifications :

as follow:


device 16f877a


INPUT portb.1 ' when you are done with sending a byte,
INPUT portb.0 'assign the pins as input pins.
input portd.2
StopBit var bit
StartBit var bit
Parity var bit
Temp var byte
DatTime var byte
ClkTime var byte




stopbit = 1
startbit = 0
Parity = 0 'for q parity=0

Temp = $15 ' Send "q" as an example.

DatTime = 10 ' Data Pause Time.
ClkTime = 50 ' Clock Pause time.

main:

if portd.2=1 then sendQ
goto main



end

sendQ:

OUTPUT portb.1 ' Before you send anything, assign the pins as output pins.
OUTPUT portb.0

portb.1 = 1
PAUSEUS DatTime
portb.0 = STARTBit ' Start bit is always zero.
PAUSEUS DatTime
portb.1 = 0
PAUSEUS ClkTime

portb.1 = 1
PAUSEUS DatTime
portb.0 = Temp.0 ' Bit 0.
PAUSEUS DatTime
portb.1 = 0
PAUSEUS ClkTime


portb.1 = 1
PAUSEUS DatTime
portb.0 = Temp.1 ' Bit 1.
PAUSEUS DatTime
portb.1 = 0
PAUSEUS ClkTime


portb.1 = 1
PAUSEUS DatTime
portb.0 = Temp.2 ' Bit 2.
PAUSEUS DatTime
portb.1 = 0
PAUSEUS ClkTime


portb.1 = 1
PAUSEUS DatTime
portb.0 = Temp.3 ' Bit 3.
PAUSEUS DatTime
portb.1 = 0
PAUSEUS ClkTime


portb.1 = 1
PAUSEUS DatTime
portb.0 = Temp.4 ' Bit 4.
PAUSEUS DatTime
portb.1 = 0
PAUSEUS ClkTime


portb.1 = 1
PAUSEUS DatTime
portb.0 = Temp.5 ' Bit 5.
PAUSEUS DatTime
portb.1 = 0
PAUSEUS ClkTime


portb.1 = 1
PAUSEUS DatTime
portb.0 = Temp.6 ' Bit 6.
PAUSEUS DatTime
portb.1 = 0
PAUSEUS ClkTime


portb.1 = 1
PAUSEUS DatTime
portb.0 = Temp.7 ' Bit 7.
PAUSEUS DatTime
portb.1 = 0
PAUSEUS ClkTime


portb.1 = 1
PAUSEUS DatTime
portb.0 = Parity ' Parity Bit.
PAUSEUS DatTime ' You must calculate Parity bit_
portb.1 = 0 'in somewhere before putting it here.
PAUSEUS ClkTime


portb.1 = 1
PAUSEUS DatTime
portb.0 = StopBit ' Stop bit is always 1.
PAUSEUS DatTime ' Have a variable named StopBit and make it 1.
portb.1 = 0
PAUSEUS ClkTime

INPUT portb.1 ' when you are done with sending a byte,
INPUT portb.0 'assign the pins as input pins.


goto main




______________________________

and it still not working ,nothing appears on the screan and if I used the 5V supply from the PC , the PC became freezing and nothing will work , if I used an auxiliarysupply the character " q " will not appear also as in the first case but the computer will not freezing !

now:

1) I thought it might be the DataTime and ClkTime values so I think to chnge them to dataTime = 18 , ClkTime=37 by using those values the period of logic one = 37us and logic zero period = 37us ( for the clock ) !! then the T=74us -> f=1/T =13.513KHz in the required range. but I didn't try it yet

2) the second reason I was thinking about (it may look crazy - but I get missed of reasons)
ok what I think:
in all the cases ever the PS/2 cable that we are use was goten from a mouse " a mouse
PS/2 cable - green - " was conntected to our Pic microcontroller !!



so do you think that one of those might be the reason of making the PC freezing and the character not appears.




AMAZING THAT AN ENGINEERES CAN'T MAKE A HARDWARE TO SHOW A SINGLE CHARACTER ON THE COMPUTER NOTEPAD

and this is still the first step on my project .

by the way thanks sayzer for your tring and for your help !! waitting to see your replay and what Ideas do you have in your mind !

[skimask]

As noted in Post #2, to get a key to be read by a PS/2 port, you have to send a MAKE and a BREAK scan code.
Looking at your code, I only see 8 data bits, some timing, etc. being sent.
Sayzer gave you good code to work with, but that's only half the battle.
And besides, shiftout should work just fine, as long as you send the right codes (see first line of this post)...

Also, you can shorten that up by quite a bit: (yes, here I go with my colons again!)

device 16f877a
input portb.1:input portb.0:input portd.2:stopbit var bit:startbit var bit
parity var bit:temp var byte:dattime var byte:clktime var byte
tempbit var bit:stopbit=1:startbit=0:parity=0:Temp=$15:DatTime=10
ClkTime=50
main:     if portd.2=0 then main
output portb.1:output portb.0:tempbit=startbit:gosub sendbit:tempbit=temp.0
gosub sendbit:tempbit=temp.1:gosub sendbit:tempbit=temp.2:gosub sendbit
tempbit=temp.3:gosub sendbit:tempbit=temp.4:gosub sendbit:tempbit=temp.5
gosub sendbit:tempbit=temp.6:gosub sendbit:tempbit=temp.7:gosub sendbit
tempbit=parity:gosub sendbit:tempbit=stopbit:gosub sendbit
INPUT portb.1:INPUT portb.0:goto main
sendbit:     portb.1=1:pauseus dattime:portb.0=tempbit:pauseus dattime:portb.1=0
                pauseus clktime:return
END