View Full Version : RL02-simulator, MFM en/de-coding

October 27th, 2009, 01:18 AM
Hello @ all,
concerning my Thread, 31-JUL-09 a new problem did come up. Background: I got a RL02 , micro-PDP-11, RLV-12 controller from the friendly people at "Computer museum München". I decided to use to use an ARM-7(lpc-p2148) microcontroller instead a PIC processor. I designed my own receiver/transmitter board ( based on 75107B and 55113 chip ) and now, I am able to see the RL02 date on my scope. I shift the serial-data in a 8-Bit register and send it to the ARM7 microprocessor bytewise and of course the other way round. My PROBLEM : The write/read data ( not the data from drive-command and drive-status ! ) are MFM de/en-coded. That's realy a complicated piece of hardware in the RLV-12 controller. With reference to the RL02 technical manual, figure 2-7 : I don't know how I can save this MFM data on the ARM-7 microprocessors memory ( SD-Card ) . In a write cycle ( 140 words ), there is no clock provided to synchronize/latch this data. Would it work, if I use the system clock ( 4.1 Mz) to get the MFM data and send it 1:1 back in a read-cycle ? Would be 3times more data but this is realy not a problem. --OR-- must I recreate the MFM logic based on a extra logic with FPGA environment. I also found a chip , AIC-250 , but not available in Germany. Anny comments and ideas are welcome.