Other Parts Discussed in Thread: AM5728
Hello, there are several postings on the web regarding this issue, but the resolution is not clear.
The beagleboard X15 uses the TPS659037 PMIC and the AM5728 processor.
There is a button on the board called PWRON which serves two functions. It is pushed after applying power to the board to power up the board; and secondly once the board is powered up, it can be pushed and held to shut down linux and the board. This button is connected to the TPS659037 pin PWRON. Hence the board requires the user to push the PWRON button after power is applied. I want the board to start booting when power is applied without requiring any button push, so that we can do remote operation. The solution proposed on the forms is to short across J5 which pulls the POWERHOLD pin on the TPS659037 high. It is stated that the processor must then boot or there will be "issues". I have not been able to find out what happens if the processor boot fails or the processor does not boot. What if any hardware damage would result? I posted this question on the beagleboard forum also; and they told me to contact TI.
An alternate solution if there really is a hardware issue: (is this viable?)
The beagleboard push button on the PWRON pin can be shorted across (as if always pushed). The PMIC would then power up the processor, but would go into LONGPRESSKEY mode after 12 seconds and then shut down the processor since PWRON button appears to be held in (this is an intended feature to shut down linux, the button has two purposes as mentioned above). From the TPS data sheet, if uboot sets LONG_PRESS_KEY.LPK_INT_CLR=0 and reads the interrupt bit to clear it before the 12 second time is up, the shutdown would not initiate. I can implement this change to UBOOT if the POWERHOLD method is not a good idea.
Thank you
