Wolfgang Draxinger wrote: > If OM[0:1]==01 || OM[0:1]==10, then the 4k of steppingstone SRAM are > mapped to 0x4000_0000...0x4000_0fff
Ah, are they ? Didn't know that. > Anyway. GCS0 means, the NOR will be mapped starting from > 0x0000_0000 and GCS3 means, nor starts at 0x1800_0000 Yup, that's what the AND does: make the NOR appear at either location, so that we can access it also when running from NAND. > The external SDRAM chip has been connected to GCS7, i.e. it is memory > bank7 at 0x3800_0000 It's actually at 0x34..., using the variable bank 6/7 size feature. See table 5-1 of the 2442 manual. Ignore the left-hand side of figure 5-1 :-) > In the schematics it is shown, that address lines > are connected by one bit shifted. Are the ? It's just the standard configuration for a 32 bit bus, see figure 5-11. The CPU takes care of shifting byte and 16-bit word accesses. > Finally, to flash the NOR flash, if I understood everything right, one > would connect the debug board to the GTA02, supply the NOR_WP line > with power (how much volts?), Ideally, between 1.3V and 1.8V. Vpp can be driven as high as 14V, but some (very old) boards have R2506 in place, so a high voltage on nNOR_WP could leak into FLASH_1V8. > One could also boot > with steppingstone enabled, i.e. OM[0:1]==00, but then only the > 0x1800_0000 mapping would be avaliable to flash the NOR. But that's good enough, isn't it ? :-) By the way, a little known "feature" of the 2442 is that OM is not latched at reset time. So things at address 0x00... change whenever AUX is pressed or releases. Took me a while to figure out why the machine obviously booted from NOR, but when I looked at it with JTAG (and no longer held AUX), it was gone ... > Well, that's about it. Did I get everything right? With the few exceptions above, yes. Good detective work :-) > Oh, one last question: I expect the NOR flash u-boot has it's very own > environment stored in NOR flash, and as such can't be changed, > without fiddling with the NOR flash write power line? Yup. u-boot in NOR is completely self-contained. This is the script that builds the NOR content: svn.openmoko.org/trunk/src/host/devirginator/mknor - Werner _______________________________________________ hardware mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/hardware
