Hi, Thanks, I'll try that thanks On 31/03/2016 22:10, Gerrit Heitsch wrote: > On 03/31/2016 09:55 PM, didier derny wrote: >> cs is low for the entire phi2 cycle >> phi2 in blue, cs in red >> >> cs is build from a cs from the bus subdivided by a 74ls138 + 74ls04 > > OK, that could be a problem since the addresses become valid somewhere > in the middle of PHI2 being low. That's why when using a RAM, you make > sure R/W can only become LOW while PHI2 is HIGH, otherwise you will > destroy data. > > Try to limit CS going LOW to the period when the addresses match _and_ > PHI2 is high. > > Gerrit > > > > >> >> >> >> On 31/03/2016 21:45, Gerrit Heitsch wrote: >>> On 03/31/2016 09:35 PM, didier derny wrote: >>>> Finally it works at even and odd addresses >>>> >>>> I observed both case with the oscilloscope ODD and EVEN addresses >>>> >>>> the differences between both case was that when the code was at odd >>>> addresses >>>> the A0 line was at the same value for the next cycle, >>>> so the hypothesis was that CH376 was removing the data to fast when A0 >>>> changed... >>>> >>>> so I added a small capacitor between A0 and GND (on the CH376) >>>> >>>> now A0 is delayed and it works where ever is the code (odd/even) >>>> >>>> how could I solve this problem properly ? >>>> I don't like this capacitor on the address bus... >>> >>> You still didn't tell us if CS is low while PHI2 is high or not. >>> Mixing this up would explain your problem... >>> >>> Gerrit >>> >>> >>> >>> >>>> >>>> thanks to all >>>> >>>> -- >>>> didier >>>> >>>> >>>> On 30/03/2016 22:08, Gerrit Heitsch wrote: >>>>> On 03/30/2016 09:44 PM, didier derny wrote: >>>>>> if I remove the board and inject a signal on A0 >>>>>> I get the signals on other pins a few mv >>>>>> a little bit higher on CS >>>>>> >>>>>> I checked with the oscilloscope >>>>>> >>>>>> CS / PHI2 with the code odd/even seems ok cs go low on falling >>>>>> edge >>>>>> of phi2 / go up on raising edge of phi2 (same for odd and even) >>>>> >>>>> Huh? According to what I could find, CS is low_active on that chip. >>>>> Meaning you need to have CS low when PHI2 is high. >>>>> >>>>> Gerrit >>>>> >>>>> >>>>> >>>>> Message was sent through the cbm-hackers mailing list >>>> >>>> >>>> Message was sent through the cbm-hackers mailing list >>>> >>>> >>> >>> >>> Message was sent through the cbm-hackers mailing list >> > > > Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing listReceived on 2016-03-31 21:00:16
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