This is more of that it could be done rather than it being needed. the EEPROM in my 1.4 Xbox (soon to be laptop xbox) uses a Winbond flash in a TSOP package (well all Xboxs use tsop EEPROMs) so I pulled up the data sheet and it seems pretty simple, the Winbond can make use of a chip enable pin (#CE) so in theory we could just piggyback the two EEPROMs. http://www.digchip.com/datasheets/d...=1046826&part-number=W49F020T-90B&show=inline There are two issues however that I need to work out. 1: the pitch on the TSOP package is über small (about half that of the ram) so lifting a pin is probably out of the question. So there is two or three options. I could Desolder the EEPROM and make a simple PCB with room for two EEPROMs and switch the #ce lines on there (no lifted pins) OR I could try and trace back the #CE line on the motherboard and hope it leads to a point where I can install a switch. The second issue is flashing and erasing the new (second) EEPROM, if I had a programmer and the appropriate adaptors I could do it pre install but I'm thinking of using the system itself. My question is; what will happen if I try and switch to a blank EEPROM whilst the unit is operating (say right before I press the button to program the EEPROM in hexen tools)? is the EEPROM only accessed at boot time?? also a side question, can I program the EEPROM through the LCP connector?? I'm trying to find the fastest way to TSOP a xbox.. thanks
You can swap flash chips (they arent eeprom) while system is powered and reflash. But you are talking about removing the existing chip to solder in a PCB. If you are doing that, just get a chip double the size and toggle the last address line? You cant connect the chip via LPC either. You can solder it to a bunch of vias though - google for the xbox eprom 29 wire mod.
SPDT switch, common point is the last address line and the other 2 are ground and vcc. Switch one way the last address line is high, switch other its low - giving you a switch to control which half of the chip you are using.
That is really neat, thanks for the top Bad_ad84! Know of where I can get a 32tsop breakout Pcb, I'm thinking the easiest way would be solder the blank chip temporarily to a breakout and connect it to the via points on the motherboard. Boot the stock Tsop and toggle the VCC or CE line (I'm thinking vcc will be easier as there is a cap for it I could easily desolder and cut power). I'm assuming that may cause issues though, correct?
