NEW DSOA MK2 SOFTWARE VERSION 3.3a for the DSOA MK2 project in EA May/Jun/Jul 1994 ================================================= Version 3.3a of the DSOA MK2 software is now available. The upgrade cost for registered owners of version 3.2 is $10, which includes postage and handling. The cost for owners of versions 1 and 2 is $15 including postage. New cost is $35 including postage. Payment can only be made by Cheque or money order payable to "TRONNORT Technology" at the address below. The new V3.3 software will be supplied with new orders to kit suppliers as from 1/4/95, however the latest version can only be guaranteed when purchased directly from TRONNORT Technology. The following are the modifications included in version 3.3a : - Improved support for operation under Windows. - Improved support for high speed machines. - Correction of possible data sample corruption. - Correction of possible problem in STOP mode. - Problem with Data Logging triggering has been fixed. - Correctly restores original port values after use. - Improved waveform toggling command. - Support for new triggering mod which allows far better triggering. ======================================================================== MODIFICATIONS FOR THE MK2 UNIT ================================ The following modifications to the MK2 unit are not necessary, however the MK2's performance will be greatly enhanced with the use of these modifications and the Ver 3.3 software. If you are having problems with the MK2 unit, these mods may provide a solution : NOTES & ERRATA : ================ The following note appeared in the Notes & Errata column in the September 1994 edition of EA. It may not have been included with kits: The link on the bottom of the PCB that is shown as connecting to pin 9 of U9b (Q-bar) should actually be connected to pin 8 of U9b (Q). Note that an enhanced version of this mod is described below. FURTHER PROBLEMS ENCOUNTED : ============================ 1) PROBLEM : Triggering is unstable in START mode. SOLUTION: Bypass R28 with a 100pF-220pF cap. 2) PROBLEM : Generally unstable triggering SOLUTION: This is a very important modification, as the DSOA MK2 design has always had a very small trigger "window". This was a compromise in the hardware to allow use of START and STOP modes. To overcome this trigger limitation, carry out the following mod : - Replace the START/STOP switch (S6) with a DPDT type. - Wire one pole of S6 (now S6a) as per the original schematic. - Disconnect the mod link on the bottom of the PCB. - Connect pin 15 of J2 (one end of the old wire mod) to the common terminal of S6b. - Connect pin 8 of U9b to the STOP side of S6b. - Connect the EOB line (pin 1, U10a) to the START side of S6b. The purpose of this modification is to allow the END OF SAMPLE signal to come from the EOB line in START mode, or the Q-bar output of U9b in STOP mode (the same as the old mod link). This makes sure that the software correctly detects the end of sampling when in START mode. Before, in DSOA TRIGGER MODE if the trigger did not occur within a certain "window" in the software, then the software will think the DSOA has finished sampling and will read in the waveform. However this waveform will not have been updated, and thus the software is just re-reading the previous waveform. Before, you had to be lucky to have the trigger point occur within the trigger window, but now the software will always wait for the DSOA to finish sampling. This modification will only be partly sucessful with the old Ver 3.2 software, however it is still a very worthwhile mod if your staying with Ver 3.2. 3) PROBLEM : Vertical inaccuracy when approaching full scale. SOLUTION: Replace R35 with a link. This "stopper" resistor forms a voltage divider with the feedback resistors in the circuit of U8b which degrades the vertical accuracy of the input amp. U8a is working as a stable rail source, and thus R35 effectively increases the source resistance of this rail to 1Kę. Replacing it with a link eliminates the problem. 4) PROBLEM : Erratic address incrementing (particulary evident in STOP mode). Software not reading exactly 32K samples. SOLUTION: Multiple clocking is occurring in the HOST MEM INC line. Bypass pin 13 of U10d to ground with a 47pF cap. ======================================================================== I am hoping to use the new EA BBS as a discussion forum and support base for the DSOA projects, once this facility of the BBS becomes available. Regards, David L. Jones TRONNORT Technology 12 Copeland Road Lethbridge Park NSW 2770. 1st April, 1995.