On 08/04/2011 06:37 AM, shawn Bai wrote: > When enlarging Nor Flash to 4GiB, the AM in OR0 is 0x0000_0, where the number > of zero is 17. > > According to what is said in datasheet, if the bit value of some bit in > address mask is 0, > then the corresponding bit in address will be masked. > > So, the higher 17 bits in address will be masked, is it right ? > > If so, the range accessed in flash is just 32KBytes from the BA in BR0. > Is that right ? But Not the same with what you mean.
The address mask applies only to matching a chip select. Once it's been matched, the full address goes to the device -- minus the bits that the device does not implement. An bit whose address mask is zero is treated the same as the least-significant 15 bits. > And from what you replied before in this question, may I say the 32KBytes > will repeat through 4GiB address space ? not 8MBytes ? No. > then, what is the effect of CONFIG_SYS_MONITOR_BASE in this ABSOLUTE branch > as uboot comment indicates ? The effect is that the program counter contains "CONFIG_SYS_MONITOR_BASE + in_flash", so that when the code later shrinks the chipselect it will still be executing from flash. -Scott _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
