The JSCCWMX53 has an autoboot circuit. This circuit is used to select if we want to press the "Power" button for booting or if we want to boot when the supplies are ON.
The autoboot circuit generates a low level pulse, simulating a power button press. This low level pulse is generated with two RC circuits. These circuits need about 1sec to be discharged when the supplies are off.
If the power supplies are powered off and on in less than 1second the autoboot circuit does not generate the low level pulse and the module does not boot automatically. In this case the user has to press the "Power" button.
Workarounds
1.- Wait for 2seconds between power off and power on.
2- Remove the J6 jumper (autoboot disabled) and always press "Power" button to boot.
There is a bit in the PMIC that overrides this circuit. In the current PMIC the AUTOBOOT bit of register 15 is set to 0, but if this bit is set to 1 the module will always boot when the power is present. This bit is configured in the OTP memory. If a customer needs this functionality we will have to make a special variant with a PMIC configuring this bit to 1.
Last updated:
Jun 06, 2019