Solution for connecting at91sam9260 to Sam-ba

For the bootloader of at91sam9260, you may often encounter the following problem: for a clean NAND Flash (that is, you have never written anything), the connection between at91sam9260 and Sam-Ba is very easy, however, after bootloader (including Bootstrap) is installed, it cannot be connected to Sam-ba.

 

To solve this problem, let's first understand the connection principle between at91sam9260 and Sam-ba. No matter what the problem is, first understanding the principle is necessary to solve the problem.

 

The following describes the connection principle and the answer from the network:

The connection between at91sam9260 and the SAM-BA is because a piece of solid code in the chip runs up before it detects the target board and establishes a connection. <Br/> assume that you have burned Bootstrap and the chip is powered on, and the code that can be run is found, so that the code that is fixed in the chip is not executed. As a result, you cannot establish a connection with the SAM-BA. The solution mainly includes the following aspects: <br/> 1. you have reserved hardware on the Development Board to handle this problem, and there is a button. Once this button is pressed, test to clear all the code in flash, this allows the chip to execute the on-chip solidified code after power-on. Of course, this requires the support of the software in Bootstrap, that is, whether the bootstrap detection button is pressed or not. If it is pressed, it is cleared. In this way, no effective and executable code can be detected when the chip is powered on. The problem is solved ...... ^ _ ^ <Br/> 2. There is also an unprofessional approach, but it is very effective. My Development Board does not have a design button, nor is it designed to clear code in Bootstrap. However, one of my tricks here is to short the address line of NAND Flash (I have no nor flash or data flash on the Board), which can be around 42 feet. The purpose of this operation is to prevent the chip from correctly carrying the code in NAND flash to the SDRAM, so the solidified code in the chip will still be executed. This solves the problem of being unable to connect to the SAM-BA. O (∩) O Haha ~ <Br/> 3. Because there is no nor flash or data flash on my board, it is only handled according to the NAND flash method. Other Flash files follow similar methods, as long as the Code cannot be correctly started. Good luck ...... ^ _ ^ <Br/> 

After understanding the principle, it is difficult to solve this problem. My board is also the same, and there is no jumper, but I did not use the method found above, instead, it is solved by transient access to the 7th and 8th pins of SDRAM, as described below:

1. Disconnect the system power supply;

2. Use tweezers to connect the 7th and 8th pins of SDRAM without releasing them;

3. The system is powered on. Wait for 4 to 5 seconds and release the tweezers. Then the connection will be successful and the corresponding serial port will be found again in Sam-ba.