"In system programming"??

Hello Dala,

There are many ways to do this. Usually there is a small piece of code "hard-wired" into the target system so it can adhere to a download protocol.

JTAG isn't always needed and can be cumbersome because of the number of wires. As an example, the MSP430 and other processors have what is called a "boot loader". This little piece of code resides on the processor right off the factory. It can be used to download the flash code simply using an RS-232 connection and protocol. IOW, the processor comes with a little bit of intelligence even before it has been programmed for the very first time by you.

Regards, Joerg

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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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Dala Dahlgren

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