Thanks, Scott. -Shawn
---------------------------------------- > Date: Mon, 8 Aug 2011 15:42:38 -0500 > From: [email protected] > To: [email protected] > CC: [email protected] > Subject: Re: [U-Boot] problem with mpc837x start.S > > 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 [email protected] http://lists.denx.de/mailman/listinfo/u-boot
