leowjunwei

hi Tony I thank youur help in getting me started on pure logic for my keyboard converter project but i realize doing it in micro-controller way will need less effort as what u mentioned and the chip i am using it PIC16F84. i found a good website to get me started.It provides the final asm file and the schematic.I am not sure if you can help me with this.this is the link: h**p://www.technology.niagarac.on.ca/students/j/cjones/ i have problem understanding this section of code.How does the developer use 138 to generate baud rate of 1200? ********Main Program******************** receive the data at 1200 baud rate call Delay3 call Delay3 *******Delay3-used for RS232, provides a baud rate of 1200***** Delay3 movlw .138 movwf count3 dec3 decfsz count3,f goto dec3 return ******************************************************** please advise. thanks..

Hi Tony, happy new year to you! hope you have a great celebration yesterday. P.S: i think you forgot to upload the schematic file on your post.It wasnt on the post:) thanks regards

Hi Tony, Just wanna wish you a happy new year eve, and hope 2006 will be a great year ahead for you:) Nice to know you through forun.stay in touch, and will get back to you later today. Have a good celebration. regards

Hi Tony, i am impressed with the schematic you managed to draw up at such short span of time. Have you tested the circuit on a computer simulation software by sending in 9600bps? Q1: Will you mind explaining in words,a summary of how the whole circuit functions, so that it will be easier for me to follow? i will not mind spelling errors:) Q2: Will you mind explaining abit further on how each of the counter works and the rationale for connecting one counter to another,esp the connection which involves R1 and C1 to set up a time delay? how can it be achieved? Q3: For the ceramic capacitors,you asked me to connect them to each chip..Do you mean connecting them to the Vcc pin or GND pin etc? thanks alot junwei

Hi Tony, 1. If I send the string “1CF01C” for ASCII character ‘a’ from the 1st PC, will I be sending the correct sequence of bits from LSB to MSB so that the keyboard controller at the 2nd PC will treat the string as a set of scancode? 2. If I do set the baud to be between10kbps-20kbps from the PC software, I will then be able to generate RS232 data at a rate similar to a typical keyboard clock frequency. If the data is passed through a MAX232 chip, it can then be converted it into a TTL/CMOS 0-+5v data to be used as keyboard data. Is my concept so far correct? 3. So at this stage, my main concern is to synchronize the PS/2 clock to the data so that they can be transmitted and correctly interpreted by the keyboard controller at the 2nd PC? Thanks Regards

hi tony, I will appreciate if i can built the hardware interface by using pure logic TTL/CMOS etc..I am not familiar with microncontroller at all. as i want the keyboard freq to be between 10k-20khz. Can i set the baud rate for my RS232 data to be within the range and then sent it down the serial link? Then i just need to add another clock(10k-20khz) to synchronize with the incoming RS232 data.But i am not sure about if this will work. i wanted the RS232 protocol to work as keyboard protocol so that the keyboard controller at the 2nd PC can receive and interpret the scancode correctly. thanks regards

hi, I am exploring various ways to get data across to 2nd PC terminal. I have tried the software method.I have written a software at the 2nd PC to retrieve the data and upload to any active window.IT has been sucessful. Now i am exploring the method to get RS232 data across to 2nd PC using a hardware method.that is RS232(PC)->PS/2(PC). This wil then create a hardware device independent of operating system and also save the trouble to build a software in the 2nd PC.

Hi tony, I really appreciate yur assistance.Before i jump into real discussion on what you have given me for the schematic..i will like to show you a full summary attachment of my project and what i have come up with so far. The commercial product is close to what i wanted to built for the hardware interface circuit. In fact, i wanted to use pure logic (logic gates,CMOS,TTL,74's series etc) to build the hardware interface as i am not very familiar with PLL and microcontroller.Is there a way to use pure logic in this case? thanks a lot application.zip

hi tony, i greatly appreciate what you have come up so far.its an interesting project which have wide applications.Just that now i am stuck with the hardware..and the conversion of RS232 data stream to PS2 is giving me lots of headache. Qn1: As what you said, i can use RTS/CTS signal to generate directly PS2 stream? How is that possible.. i am sending RS232 stream from transmitter. P.S: i will be most grateful if you could have a drawing schematic to guide me along.. thanks regards junwei

hi Tom and the rest, Ans1: the first PC make a coding in to PS2 format. That means i just code it to send 'a' as "ICF01C" instead. So its like sending PS/2 keyboard data scancode. Ans2: the cables shouldnt be more than 2 metres..the 2 PCs are side by side only. Qn1: i am not familiar with microcontroller..Actually,i thought i could just implement the circuit using normal IC chips and some FFs as what i uploaded in the schematic.Can i use some simple circuit instead, and can help me to find out if i can build something similar to my schematic? thanks

hi Tony_Stoynov and the rest, Option 2 is exactly what i want to achieve. But i just do not know how to get it started. i have drawn out a schematic..not sure if its correct..take a look at the attachment

sorry.below will be a clearer explanation of my project ----------------------------------------------------------------------- I have written a C++ application for sending RS232 serial data in single PC and I want the data to be received on another PC and captured as keystrokes. These keystrokes can then be used in any window’s word applications and appeared as though they are typed from the keyboard. I have also coded the program such that for each ASCII character, it is converted into it’s corresponding set of scancode. For example,’a’ is translated into IC FO IC and sends as string “ICF0IC” over the serial link. This ensures the scancode is correctly interpreted by the keyboard controller on the receiver’s side PC. However I do not know how to go about implementing a hardware device that can achieve the conversion of RS232 data to keyboard data.

hi everybody I have written a C++ application for sending RS232 serial data in single PC and I want the data to be received on another PC and captured as keystrokes. These keystrokes can then be used in any window’s word applications and appeared as though they are typed from the keyboard. I have also coded the program such that for each ASCII character, it is converted into it’s corresponding set of scancode. For example,’a’ is translated into IC FO IC and sends as string “ICF0IC” over the serial link. This ensures the scancode is correctly interpreted by the keyboard controller on the receiver’s side PC. However I do not know how to go about implementing a hardware device that can achieve the conversion of RS232 data to keyboard data.