On Sun, 29 Nov 1998 18:56:48 +0000 "Peter L. Peres" writes: >On Sat, 28 Nov 1998, Morgan Olsson wrote: > >> I thougt it was the same (shift register technique) > >Microwire is (C) [pat] [tm] Motorola, whereas SPI is an acronym that >cannot be patented... "Microwire" is National's TM. "SPI" is Motorola's name. Neither seems to have has been too actively sueing other manufacturers for re-using their names. >The addressing refers to the fact that some SPI part manufacturers >choose >to address distinct functions in a chip by the number of clock pulses >until ~SS is (un)asserted. Motorola is one of these BTW. Motorola I think first used this feature and named it "BitGrabber" TM. The number of pulses is always a multiple of 8 though. That to me seems to be the major difference: SPI devices try to group the data into bytes of 8 because the SPI master hardware in Motorola processors always sends 8 bits at a time. Microwire devices are harder to deal with because they send various lengths of data. For example to upgrade from a 93C46 to 93C56 EEPROM would require modifying the sending routine to send an additional bit of address. ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866]