Hi,
DM642 bootmode is selected via pull-up and pull-down resistors on AEA22
and AEA21 address lines. The state of these pins is latched during reset
and selects the boot source. The DM642 has internal pull-down resistors on
these pins. For PCI/Host boot mode, AEA22 must be left open (or pulled
down), and AEA21 must be pulled high. Use a 2K2 or smaller pull-up resitor.
Regards,
Adolf Klemenz, D.SignT
At 01:56 27.04.2007 +0000, onlyflyer wrote:
>Hi:
>I'm writing a linux driver for C64(board dm642).In order start DM642
>in linux host,I do things as follow:
>1)warm reset c64
>2)init emif for dm642
>3)mmap the c64's iram to userspace
>4)set c64's memory zero
>5)load c64's bin file to iram
>6)trigger dspint to start c64
>
>BUT,i doesn't work.When i clear the c64's iram, the whole system
is
>crashed.
>
>I find that C64 is not in pci boot mode,the value of HDCR is 0.So,i
>think maybe this is the problem.
>
>I read c64's datasheet again and again,I can't find how to enable
c64's
>pci boot mode.HDCR's PCIBOOT bit is read only.
>
>So,my questions are:
>1,how to enable DM642's pci boot mode.
>2,when I write sth. DM642's iram, why my host crashed?
>
>Can anyone help me?
>
>Thanks in advance.
>