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Reading A Ps/2 Keyboard.
I JUST FOUND THIS SITE VERY USEFUL (PDS CODE) AND THE CODE WORKED WITH ME. i COULD DECODE THE PS/2 KEYBOARD ATTACHED TO THE PIC ON THE LCD.
SORRY FOR PUTTING UP A PDS CODE. CAN ANYONE CONVERT IT FOR PBP. IT HAS A LOT OF ASM, WONDER WHY ?
http://users.picbasic.org/Howto/PC_k...c_keyboard.htm
REGARDS
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Good suggestion.
I think i need to take your suggestion and shut my mouth about it.Originally Posted by keithdoxey
regards
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Why don't you try converting it over. Then if/when it doesn't work, we'll help you figure out why it doesn't work.
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Hi guys,
I was wondering if someone can help me out here on a simple task.
I've been learning a lot by reading about sending data to a keyboard's PS/2 port, but I am unable to send a simple letter and have it show up in notepad.exe on the host computer.
I know the following: data sent must have Start Bit = 0, Scancode (LSB First), Odd Parity, Stop Bit = 1.
Now, I don't care about keyboard initialization, because I will be booting up the PC with a normal keyboard attached, then swapping out the keyboard with my device.
All I want to do is send the letter 'q' ($15).
I am doing so by sending q (0+$51+0+1), then the release code (0+$0F+1+1), then q again (0+$51+0+1).
However, I am not getting anything on the host side of things.
Here is my code:
Any advice appreciated.Code:; PS2SendCode ; ; PIC16F648A ; _________________ _______________ ; 1|RA2/AN2/VREF RA1/AN1|18 ; 2|RA3/AN3/CMP1 RA0/AN0|17 ; 3|RA4/TOCKI/CMP2 RA7/OSC1/CLKIN|16 ; VPP ---> 4|RA5/MCLR/VPP RA6/OSC2/CLKOUT|15 ; Gnd 5|Vss Vdd|14 +5 ; 6|RB0/INT RB7/T1OSI/PGD|13 <--- PGD ; 7|RB1/RX/DT RB6/T1OSO/T1CKI/PGC|12 <--- PGC ; 8|RB2/TX/CK RB5|11 <--> PS2DATA ; PUSH BUTTON ---> 9|RB3/CCP1 RB4/PGM|10 <--- PS2CLK _|¯|_|¯|_|¯|_|¯|_ ; ---------------------------------- ; ;=============================================================================== ; Keyboard to Host Protocol ; ___ _ _ _ _ _ _ _ _ _ _ _ _ ___ ; CLOCK |__| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| ; ; DATA | S | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | P | E | ; ; S = start bit = 0 P = odd parity E = stop bit = 1 ; data valid on falling edge of clock ;=============================================================================== @ errorlevel -223,-207,-306 ; Suppress useless messages @ LIST P=PIC16F648A @ __CONFIG _INTRC_OSC_NOCLKOUT & _WDT_ON & _MCLRE_OFF & _CP_OFF & _BODEN_OFF & _PWRTE_OFF & _LVP_OFF ;Using 4MHz oscillator define OSC 4 ;DEFINE SHIFT_PAUSEUS 43 PortB = 0 'Clear Port B INTCON = 0 'Interrupts Off CMCON = %00000111 'Disable Comparators OPTION_REG.7 = 0 'Enable Port B Weak Pull-Ups BitCnt VAR BYTE KBTimeout VAR BYTE ScanCode VAR Word Parity Var BYTE StartButton Var PortB.3 PS2Clk var PortB.4 '0 PS2Dat var PortB.5 '0 TRISB = %11111111 'Set PORTB pins direction to input Start: pause 500 if startbutton = 0 then: goSUB StartSend goto start StartSend: 'SEND Q ($15 LSB FIRST) Parity = 1 'Odd parity scancode.0 = 0 Gosub sendbit 'send START BIT scancode = %00010101 'send 'q' For bitcnt = 1 To 8 'set for 8 data bits Gosub sendbit 'send DATA BIT If scancode.0 = 1 Then: parity = parity + 1 scancode = scancode >> 1 'shift out next bit Next bitcnt scancode.0 = parity.0 Gosub sendbit 'send PARITY BIT scancode.0 = 1 Gosub sendbit 'send STOP BIT 'SEND RELEASE ($F0 LSB FIRST) Parity = 1 'Odd parity scancode.0 = 0 Gosub sendbit 'send START BIT scancode = %11110000 'send '$F0' For bitcnt = 1 To 8 'set for 8 data bits Gosub sendbit 'send DATA BIT If scancode.0 = 1 Then: parity = parity + 1 scancode = scancode >> 1 'shift out next bit Next bitcnt scancode.0 = parity.0 Gosub sendbit 'send PARITY BIT scancode.0 = 1 Gosub sendbit 'send STOP BIT 'SEND Q ($15 LSB FIRST) Parity = 1 'Odd parity scancode.0 = 0 Gosub sendbit 'send START BIT scancode = %00010101 'send 'q' For bitcnt = 1 To 8 'set for 8 data bits Gosub sendbit 'send DATA BIT If scancode.0 = 1 Then: parity = parity + 1 scancode = scancode >> 1 'shift out next bit Next bitcnt scancode.0 = parity.0 Gosub sendbit 'send PARITY BIT scancode.0 = 1 Gosub sendbit 'send STOP BIT Return SendBit: 'Looking for keyboard clock and data line to go high, then send data bit to it! ;If NOT(PS2Clk = 1 AND PS2Dat = 1) Then sendbit 'loop until clock line goes low PS2Dat = scancode.0 'send data bit return
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Take a look at post #6 at
http://www.picbasic.co.uk/forum/showthread.php?t=7962
Also, I am not sure about the way you control the Clock line in your code.
"If the Earth were a single state, Istanbul would be its capital." Napoleon Bonaparte
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Yeah, your code seems to indicate that you are waiting for the clock line to do something?
Your device must generate the clock in this case.
"I think fish is nice, but then I think that rain is wet, so who am I to judge?" - Douglas Adams
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Ok, I misunderstood.
I now realized that you are SENDING data TO KB;
Not reading from it.
Sorry about that.
------------------------
"If the Earth were a single state, Istanbul would be its capital." Napoleon Bonaparte
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rookie11, I don't think this code will ever work. Where are the ENDIF commands to terminate the IF statements?
Dave Purola,
N8NTA
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One line If/Then statements....don't need an ENDIF....
If this=0 then gosub dothis : that=1 : goto something
...valid statement
If this is zero, then gosub dothis, set that to 1, then goto something.
But that colon following the THEN in the code a few posts back looks a bit strange to me...
And I know colons!
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skimask , Look before you leap.... Look at where the colon lies........
Dave Purola.
N8NTA
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Well, I was talking about the code attached above. He has this line (along with another that's the same way):
If scancode.0 = 1 Then: parity = parity + 1
----------------------^
I don't know how that'll compile, if it will compile good and not cause an error, if it'll work as written, or what will happen. It just doesn't look right to me, that's all...
And I'm always keeping track of where my colon's lie...
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skimask, The way I interpret a colon is to terminate a line of code and, allow the start of another command string to be placed on the same line. If this is the case then all of his IF/THEN statements should have and ending ENDIF command. I have not tried this as I never write code in this fashion. It is much to confusing and hard to follow the flow... Have you ever tried this format? If it works then GREAT...
Dave Purola,
N8NTA
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I guess I use whatever fits/works and takes up as few actual lines on the screen.
As far as being confusing, well, I usually don't write code for other folks (reference the High Colonic Master
But, I'm going to play with the If/Then colon format thing tonight when I get home and see what happens...
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Are you guys looking to emulate a PS/2 keyboard or get data from a PS/2 keyboard?
I have pure PBP code for both if you need it.
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May I see the emulation code, then?
IF, of course, it is responding to the system commands ??
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"If the Earth were a single state, Istanbul would be its capital." Napoleon Bonaparte
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I second that commotion...no sense reinventing the wheel...
It's the responding back to the PC bit that gets me...
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PJALM's
is possible upload the code?
i use http://www.picbasic.co.uk/forum/arch...hp/t-2736.html but not work leds
many thanks
..: Don't worry, be happy :..
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Where have I seen that thread before? Guess I'll go to Post #1 and read through it again and try to figure it out. (i.e. endless loop)
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Ski, I did not quite understand what you meant but,
PC (system) can terminate the communication while KB is sending data to it AND send system commands to it to have it do something; turn on/off status leds, resend last byte etc...
The thing is to detect this termination thingie during an active transmission.
This is what I meant.
"If the Earth were a single state, Istanbul would be its capital." Napoleon Bonaparte
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Ok, I was talking about the initial comm's to the keyboard when the PC powers up. It's been discussed in a couple of other threads somewhere.
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I am interested in code to emulate a PS/2 keyboard using a 16f88 interfacing to an embedded PC. Is it possible to view your PBP code?
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PBP code for PS/2 emulation
showed the carrot and now missing in action.
Where is the guy with the PBP code ?
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i have to do 4x4 scan key to ps2 intf. with (one time) programmable keys, numeric part + some fonction key ie. P, A, X, Y...
but I'm not shure is it a lot of work in that system area,: tx ack, rx sys requests, init in PCstart, and others, if there is a way to put paralel with old kb board to do that portion, (if I dont hawe to switch betwen) then, sems to be easy ?
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PS2 emulation is harder than it seems. Maybe possible to fit a PIC in parallel of an existing controller, but i feel some potential bit collision one day or another.
I've done it with a single PIC, and frankly... enough time spent and wasted on it to hate it now
Last edited by mister_e; - 4th May 2008 at 19:31.
Steve
It's not a bug, it's a random feature.
There's no problem, only learning opportunities.
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I've seen keyboard emulators in different gaming forums (mostly mame related), where it IS put in parallel with the keyboard.
anyways, I came across this function/macro/whatever for reading a ps/2 keyboard in great cow basic. says it's free and ok to copy sooo...
don't know if it'll do anyone any good, but....Code:' PS/2 keyboard/mouse routines for Great Cow BASIC ' Copyright (C) 2006 Hugh Considine ' This library is free software; you can redistribute it and/or ' modify it under the terms of the GNU Lesser General Public ' License as published by the Free Software Foundation; either ' version 2.1 of the License, or (at your option) any later version. ' This library is distributed in the hope that it will be useful, ' but WITHOUT ANY WARRANTY; without even the implied warranty of ' MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ' Lesser General Public License for more details. ' You should have received a copy of the GNU Lesser General Public ' License along with this library; if not, write to the Free Software ' Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA '******************************************************************************** 'IMPORTANT: 'THIS FILE IS ESSENTIAL FOR SOME OF THE COMMANDS IN GCBASIC. DO NOT ALTER THIS FILE 'UNLESS YOU KNOW WHAT YOU ARE DOING. CHANGING THIS FILE COULD RENDER SOME GCBASIC 'COMMANDS UNUSABLE! '******************************************************************************** #define PS2Data SysTemp.0 'Set to data pin #define PS2Clock SysTemp.0 'Set to clock pin #startup InitPS2 'Initialise sub InitPS2 DIR PS2Clock IN DIR PS2Data IN KeyShift = 0 MouseX = 0 MouseY = 0 end sub 'Return ASCII value of input key function INKEY 'Initialise, and get key scan code INKEY = 0 ScanCode = PS2ReadByte if ScanCode = 0 then exit function '2-byte key? if ScanCode = 0xE0 then do while INKEY = 0 INKEY = PS2ReadByte loop INKEY = INKEY OR 128 end if 'Shift/Capslock if ScanCode = 0x12 or ScanCode = 0x59 then KeyShift = 1: exit function if ScanCode = 0x58 then if KeyShift = 2 then KeyShift = 0: exit function KeyShift = 2 exit function end if 'Translate scan code to ASCII 'Control Chars if ScanCode = 0x5A then INKEY = 13 'Enter if ScanCode = 0x66 then INKEY = 8 'Backspace if ScanCode = 0x76 then INKEY = 27 'Esc if ScanCode = 0x29 then INKEY = 32 'Space 'Arrows 'Numbers if ScanCode = 0x45 then INKEY = 48 if ScanCode = 0x16 then INKEY = 49 if ScanCode = 0x1E then INKEY = 50 if ScanCode = 0x26 then INKEY = 51 if ScanCode = 0x25 then INKEY = 52 if ScanCode = 0x2E then INKEY = 53 if ScanCode = 0x36 then INKEY = 54 if ScanCode = 0x3D then INKEY = 55 if ScanCode = 0x3E then INKEY = 56 if ScanCode = 0x46 then INKEY = 57 'Letters if ScanCode = 0x1C then INKEY = 65 'A if ScanCode = 0x32 then INKEY = 66 if ScanCode = 0x21 then INKEY = 67 'C if ScanCode = 0x23 then INKEY = 68 if ScanCode = 0x24 then INKEY = 69 'E if ScanCode = 0x2B then INKEY = 70 if ScanCode = 0x34 then INKEY = 71 'G if ScanCode = 0x33 then INKEY = 72 if ScanCode = 0x43 then INKEY = 73 'I if ScanCode = 0x3B then INKEY = 74 if ScanCode = 0x42 then INKEY = 75 'K if ScanCode = 0x4B then INKEY = 76 if ScanCode = 0x3A then INKEY = 77 'M if ScanCode = 0x31 then INKEY = 78 if ScanCode = 0x44 then INKEY = 79 'O if ScanCode = 0x4D then INKEY = 80 if ScanCode = 0x15 then INKEY = 81 'Q if ScanCode = 0x2D then INKEY = 82 if ScanCode = 0x1B then INKEY = 83 'S if ScanCode = 0x2C then INKEY = 84 if ScanCode = 0x3C then INKEY = 85 'U if ScanCode = 0x2A then INKEY = 86 if ScanCode = 0x1D then INKEY = 87 'W if ScanCode = 0x22 then INKEY = 88 if ScanCode = 0x35 then INKEY = 89 'Y if ScanCode = 0x1A then INKEY = 90 'Z if INKEY >= 65 and INKEY <= 90 and KeyShift = 0 then INKEY += 32 'Symbols if ScanCode = 0x0E then INKEY = 96 '` if ScanCode = 0x4E then INKEY = 45 '- if ScanCode = 0x55 then INKEY = 61 '= if ScanCode = 0x5D then INKEY = 92 '\ if ScanCode = 0x4c then INKEY = 59 '; if ScanCode = 0x52 then INKEY = 39 '' if ScanCode = 0x41 then INKEY = 44 ', if ScanCode = 0x49 then INKEY = 46 '. if ScanCode = 0x4A then INKEY = 47 '/ if KeyShift = 1 then KeyShift = 0 end function function PS2ReadByte PS2ReadByte = 0 if PS2Clock ON THEN exit function 'Start Bit wait until PS2Clock OFF if PS2Data ON then exit function wait until PS2Clock ON '8 data bits For PS2Bit = 1 to 8 wait until PS2Clock OFF set STATUS.C OFF if PS2Data ON then set STATUS.C ON ROTATE PS2ReadByte RIGHT wait until PS2Clock ON next 'Parity wait until PS2Clock OFF wait until PS2Clock ON 'End wait until PS2Clock OFF wait until PS2Clock ON end function sub PS2WriteByte (PS2Byte) #NR 'Take control dir PS2Clock Out set PS2Clock Off wait 12 10us dir PS2Data Out set PS2Data Off dir PS2Clock In 'Start Bit wait until PS2Clock on wait until PS2Clock off PS2Parity = 0 '8 data bits For PS2Bit = 1 to 8 if PS2Byte.0 Off then Set PS2Data off if PS2Byte.0 On then Set PS2Data on: PS2Parity += 1 ROTATE PS2ReadByte RIGHT wait until PS2Clock ON wait until PS2Clock OFF next 'Parity if PS2Parity.0 off then Set PS2Data on if PS2Parity.0 on then Set PS2Data off wait until PS2Clock ON wait until PS2Clock OFF 'Stop set PS2Data On wait until PS2Clock ON wait until PS2Clock OFF 'Ack Set PS2Data Off wait until PS2Clock ON dir PS2Data in wait 100 10us end sub
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Thanks Michael
Hi Michael,
I used your routine and it saved my life. Works like a breeze. Thanks for the great job and sharing it on this forum..
Regards
Sougata
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Routine
Hi Sougata:
Good day Bro, Can you share with me the routine?
Ryan
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The code is right in this thread
Hi,
The code is right in this thread as a zip attachment. I used it along with DT's Interrupt system and it worked fine.
Regards
Sougata
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PS/2 to 18F4620 timing issues with mytekcontrols code?
Hello!
I have implemented the wonderful code PS/2 keyboard code from mytekcontrols in my PIC18F4620. It will only work if I set
TOcntDLY CON to a value of 100 (originally set to 10 per mytekcontrols).
Furthermore, if I hit and hold any of the these three keys (Caps Lock, Num Lock, or Scroll Lock), there is no response from the keyboard LEDs and the program just hangs. These keys will work if I hit them VERY quickly (less than .1 second - just hit with a glancing blow).
Everything else works as it should (with the CON change above).
Is this a big timing issue for me? Settings when programming?
Reference:
PIC 18F4620
Internal OSC at 8Mhz
OSCCON = %01110010
BUT even with an external 20Mhz oscillator, same performance, still hangs!
I sense severe timing issues. I will welcome all suggestions with regard to fixing this code for me.
Thank you to all,
Bob Pigford
Newark, Delaware
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May not be
Hi,
I used it on a 40MHz oscillator and did not have any issue. However the following may be considered:
1. Allow enough time (2 seconds or more is safe) before calling the PS2init routine. Your keyboard needs this to boot-up. Indicated by all three LEDs flashing and going off.
2. The characters are stored using interrupts but the interrupts are re-enabled only when parse it. This may cause the keyboards internal buffer to be overwhelmed.
Regards
Sougata
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PS/2 to 18F4620 timing issues with mytekcontrols code?
Thank you sougata,
I did allow enough time for the keyboard to start. I see the LEDs flash, so I think that is not the issue.
I will follow you suggestion and look into the buffer situation. I will also order a 40mhz oscillator just to be sure.
I will report back on my progress.
Thank you again,
Bob Pigford
Newark, Delaware, USA
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PS/2 to 18F4620 timing issues isolated to "putkey" routine
I just isolated the issue! If I eliminate any output going TO the keyboard, everything works just fine! I disabled the "putkey" routine buy placing a "RETURN" immediately after the beginning of the routine.
Even with the internal oscillator at 8mhz, it all works very well (even with "TOcntDLY set back to 10)! I can live without seeing the LEDs on the keyboard for now. When my 40mhz oscillator arrives, it will try it again and report back.
Regards,
Bob
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Use HSPLL
Hi,
Every PIC18 has got a x4 HSPLL oscillator mode. So you can use an external 10MHz crystal to effectively get 40 MHz Fosc. For internal 8MHz you need to configure osccon to enable HSPLL and get 8 x 4 = 32MHz from the internal oscillator.
Regards
Sougata
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Will try HSPLL
Thank you Sougata. I will give this a try and report back. And thank you for teaching me about HSPLL.
Regards,
Bob
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