Dala Dahlgren
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 Posted:
Thu Feb 10, 2005 3:45 am Post subject:
"In system programming"?? |
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I have a couple of questions regarding "in system programming", for example
programming a FlashROM after it has been soldered onto the circuit-board.
Say that you have a circuit-board with a blank FlashROM on it. To be able to
get something into the Flash you have to access it from "ouside" since the
system is not yet able to boot. I understand that the JTAG interface is
often used for this. Are there any other ways to do this if JTAG is not
supported?
How is it done on PC's, for example, when they are manufactured. Is the BIOS
burnt befor it is soldered onto the PCB, or is it possible to access the
FlashROM from "outside" on a PC. Do they use JTAG?
I have looked at a "system on chip" from SIS, the SIS55X, which is
"PC-compatibel" (Intel 80x86 compatibel). The SIS55X has no JTAG support,
but it has support for something called LPC. Can LPC be used for programming
the flash "in system"? Or how would you program a flash on a SIS55X system
with no JTAG support?
I have also noticed that some PCs have got this LPC-connector on the PCB (I
don't know if all PCs have it). Is this how they typiacally program the BIOS
on a PC? If not, how is done? Is the chip burnt before it is soldered on the
PCB? Is JTAG common on PC's?
I hope someone can give me some answers....
Thanks in advance,
dala
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