Pin descriptions sheet attached to Design Guide (DG) v1.0 I says that MODULE_SHDN_N would be “Force Power Off Request, I2S5_SDATA_OUT, DMIC1_CLK, or GPIO” and its direction would be input.
When I look at the A04 carrier board design I can see that MODULE_SHDN_N is an output from Jetson AGX Orin (JAO?) and an input to the Button MCU.
MODULE_SHDN_N is not illustrated in DG/Power block diagram.
I think I have understood JAO power up sequence - MODULE_POWER_ON is the important signal and POWER_BTN_N is simply ignored.
I haven’t yet understood power down sequence completely. As JAO is a computer system with r/w file systems I think it is always best to ask the software to shut down - with shutdown command or with power key.
DG/power down sequence controlled case suggests that if I need to force power off I should take SYS_RESET_N low, wait for CARRIER_POWER_ON to go low and then take MODULE_POWER_ON low. Is that correct?
Could you please explain what is the role (and direction) of the MODULE_SHDN_N signal.
- DG/Power and system pin descriptions say it would be SoC pin GP67 but I cannot find Orin GP67 anywhere else. Anyway it seems MODULE_SHDN_N is not a dedicated HW pin and without SW support (e.g. blank JAO) it does nothing?
- Can I start a power off sequence by pulling MODULE_SHDN_N low?
- If MODULE_SHDN_N is an output / bidir what can it be used for? Is there e.g. a fixed delay between MODULE_SHDN_N going low and… CARRIER_POWER_ON going low?
I would like to avoid a Button MCU. These days MCUs are hard to get and having an MCU would mean yet another firmware and yet another programming operation.
I hope we don’t have to implement sleep (SLEEP_REQ_N and MODULE_SLEEP_N) as that would open up another can of worms :D