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Robert: Here is some comprehensive and very impressing information I have received via E-mail. This great guy want to share his information with all the people who has an EW-904B programmer. I will let him introduce himself: Walter: I'm using a EW904B too, for more than 12 years! I'm a hardware freak, otherwise you don't need a programmer!!! Many years ago I had enormous problems with the I/O address of 390H and the address range it uses. There were conflicts with my soundblaster, overlapping of the I/O range, caused by a very stupid addressing in the SB16. Someone has forgotten to include some lower address bits, by adressing the MIDI channel it addresses 32 bytes at the same time. 380H - 39FH. I changed my EW904B, put an inverter in one of the address lines, I/O start point moved from 390H to 290H. Very quiet over there!!! After some headache and disassembling it appeared to be very simple to patch the software: only changing 1 (ONE) byte , the I/O vector, at the start of the program. I don't know which version I have, while typing this email. I also changed the hardware on pin 26 (Vcc with 2716/2732) to make it work better and faster as an A13 address line. Had too many killed chips....... before no problems in a 386SX and older slower machines, but they came in a 486DX2 in the early ninety's, that was tricky. Needed a change. Interested??? Hereby you receive a sign of life after my mail to attend you on lots and lots of info I have about the 904 series Sunshine programmers. After many measuring sessions and testing I have some simple information TXT files. (Here as web pages). Probably they will change and in the future you will receive an update. The info is very, very informative for those just like me: the solder/ hardware enthousiasts. Paperwork from the past is "rebuild" (the last weeks). In total 9 sheets. 4 for the 904B, 1 for an update for A13 - the hex 1000H error, and 4 for the 904BN. I have completely reverse engineered both programmers. And analysed their problems an how to cope with them. I also designed programming adapters for the 904 series (in multibank method) for "bigger" eproms, one for: 271000, 1001, 2000 and 2001 eproms in Jedec as well as in ROM mode, programmed in 27C128 mode banks. And one adapter for 27C4000 eproms here programmed in 27C256 mode banks. I also made some photographs. (Here visible on the main EPROM page) Walter Geeraert The Netherlands walterg@cumail.nl |
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