S912ZVL64F0VLCR's BCTL PIN OUTPUT

[Caleb1]

What is the state of S912ZVL64F0VLCR's BCTL without program? What is the output voltage?

What is the status of the program? What is the output voltage?

[danielmartynek]

Hi @Caleb1,

While the debugger is attached, the MCU is in the Special mode, and the register can be written more than once.

But when the MCU runs stand-alone without the debugger, the MCU is in the Normal mode, and the register can be written only once.

Make sure that the register is written only once in the project.

S12ZVL RM rev.2.49, Section 4.3.2.1 Mode Register (MODE).

Regards,

Daniel

[danielmartynek · Accepted solution]

Hi @Caleb1,

Out of the system reset, both regulators, the one with the internal ballast transistor and the one with the external ballast PNP are enabled.

The external regulator has a slightly higher regulating point (5V) than the internal regulator (4.95V).

That means that the external regulator tries to regulate the VDDX voltage higher and opens the PNP (BCTL voltage is slightly lower than VSUP)

Once the SW writes EXTXON = 0, INTXON = 1, the external regulator is disabled, that means Vemitter (VSUP) = Vbase (BCTL).

For this reason, the BCTL pin must be left unconnected if the PNP is not used.

Regards,

Daniel

[Caleb1]

Hi 

During the software debugging phase, setting registers makes it easy to open external pipes;

But after a slight increase, the external pipe couldn't be opened. Why is this?

What does the figure indicate as normal mode? When debugging, do you think it's not in normal mode?

What would it be like to write only once. Will the external pipes be turned off?

Thanks!

[ramprakash08]

The BCTL (Bootstrap Control) pin of the S912ZVL64F0VLCR is an output pin. Without a program, the state of the BCTL pin is typically undefined. It's important to note that the actual state can depend on the specific conditions of your system, such as power supply voltage, temperature, and the state of other pins.

The output voltage of the BCTL pin without a program can also vary depending on the conditions of your system. However, it's generally safe to assume that the output voltage will be within the range specified in the S912ZVL64F0VLCR's datasheet under the 'Electrical Characteristics' section.

When a program is running, the state and output voltage of the BCTL pin will depend on the specific instructions executed by the program. For example, if the program sets the BCTL pin to a high state, the output voltage will be close to the supply voltage (VDD). If the program sets the BCTL pin to a low state, the output voltage will be close to ground (VSS).

[Caleb1]

The current client's schematic design is the same as the schematic design provided

Adverse phenomenon: The normal output voltage of VDDX is 5V, but now it is 2.906V. The circuit behind this pin has been disconnected

Defective rate: The customer produced 60 sets and encountered 2 sets of this issue. If the power is cut off and then turned on again, the fault will disappear. I have done hundreds of power ups and downs, and this bad phenomenon will recur seven or eight times

The customer uses a normal board, erases the chip code, and then powers it on again. The output voltage of VDDX is 3.3V

[danielmartynek]

Already under a discussion here:

https://community.nxp.com/t5/S12-MagniV-Microcontrollers/S912ZVL64F0VLCR-question/m-p/1706157/highli...