Hello,
I am using FS6500 series SBC with fail-safe configuration. (Select resistor connected to GND).
But something confuse my mind. According to main state and fail safe state machines(Below) if SBC goes to normal mode ONCE, SBC can not go to LPOFF mode with ignition input. Is this right?
Best Regards,
Alican OZPAY
Hi Alican,
The main state machine has three LPOFF modes with different conditions to enter and
exit each LPOFF mode.
LPOFF - sleep
Entering in low-power mode LPOFF - sleep is only available if the product is in normal
mode by sending a secured SPI command. In this mode, all the regulators are turned off
and the MCU connected to the VCORE regulator is unsupplied. Only VKAM is available if
VKAM is used.
Once the 35FS4500/35FS6500 is in LPOFF - sleep, the device monitors external
events to wake-up and leave the low-power mode. The wake-up events can occur and
depending of the device configuration from:
• CAN physical layer
• I/O inputs IO_0 is also na I/O input. To use it for wake-up from LPOFF-sleep you need to set WU_IO0_1:0 to 01.
• Timer
LPOFF - auto WU
LPOFF - auto WU is entered when the device is in the INIT or normal mode and if the
VPRE voltage level is passing the VPRE_UV_L_4P3 threshold (typ 4.3 V). It can be also
entered by sending a secured SPI command if the product is in normal mode.
LPOFF - deep FS
LPOFF - deep FS is entered when the device is in deep fail-safe and if the key is off
(IO_0 is low). To exit this mode, a transition to high level on IO_0 is required. IO_0 is
usually connected to the key on key off signal.
When the deep fail-safe function is enabled, the fail-safe state machine monitors and
count the number of faults happening, in case of fault detection. As soon as either the fault error counter reaches its final value or the RESET pin remains asserted low for more than 8.0 s.
If you want to enter one of the LPOFF modes without the software, only option I see, is to hold the reset RSTB pin low for at least 8 seconds and the IO_0 must be also low, then the SBC enters LPOFF-deep FS mode and by transition of IO_0 to high level the SBC exits the LPOFF-deep FS mode.
With best Regards,
Jozef
Hi Alican,
The main state machine has three LPOFF modes with different conditions to enter and
exit each LPOFF mode.
LPOFF - sleep
Entering in low-power mode LPOFF - sleep is only available if the product is in normal
mode by sending a secured SPI command. In this mode, all the regulators are turned off
and the MCU connected to the VCORE regulator is unsupplied. Only VKAM is available if
VKAM is used.
Once the 35FS4500/35FS6500 is in LPOFF - sleep, the device monitors external
events to wake-up and leave the low-power mode. The wake-up events can occur and
depending of the device configuration from:
• CAN physical layer
• I/O inputs IO_0 is also na I/O input. To use it for wake-up from LPOFF-sleep you need to set WU_IO0_1:0 to 01.
• Timer
LPOFF - auto WU
LPOFF - auto WU is entered when the device is in the INIT or normal mode and if the
VPRE voltage level is passing the VPRE_UV_L_4P3 threshold (typ 4.3 V). It can be also
entered by sending a secured SPI command if the product is in normal mode.
LPOFF - deep FS
LPOFF - deep FS is entered when the device is in deep fail-safe and if the key is off
(IO_0 is low). To exit this mode, a transition to high level on IO_0 is required. IO_0 is
usually connected to the key on key off signal.
When the deep fail-safe function is enabled, the fail-safe state machine monitors and
count the number of faults happening, in case of fault detection. As soon as either the fault error counter reaches its final value or the RESET pin remains asserted low for more than 8.0 s.
If you want to enter one of the LPOFF modes without the software, only option I see, is to hold the reset RSTB pin low for at least 8 seconds and the IO_0 must be also low, then the SBC enters LPOFF-deep FS mode and by transition of IO_0 to high level the SBC exits the LPOFF-deep FS mode.
With best Regards,
Jozef
Hi Mr. Alican,
according to the Main state machine in the datasheet if the VPRE voltage passes the VPRE_UV_L4P3=4.3V during the INIT or NORMAL mode the SBC enters the LPOFF-Auto WU mode.
If the SBC will automatically tries to wake up itself from the LPOFF Auto WU mode, depends on how a bit 6 in MODE register is set. By default its 0, no action. It the bit 6 is set to 1, than the SBC will automatically tries to wake up from the LPOFF Auto WU mode after 1ms.
With Best Regards,
Jozef
Hello Alican,
The SBC can go in LPOFF SLEEP mode with the IO_0=1, but cannot go in LPOFF DEEP FS mode with the IO_0=1. So you are right if you meant the LPOFF DEEP FS mode, which is different from LPOFF SLEEP mode. While in LPOFF DEEP FS mode, the SBC can be woken up by bringing the IO_0 high. Therefore to enter the LPOFF DEEP FS mode, the IO_0 must be low.
While in normal mode, the device can be set to low-power mode (LPOFF-SLEEP) using secured SPI command.
With Best Regards,
Jozef
Hello Alican,
when you want to switch to LPOFF mode from Normal mode with secured SPI command, you should send the command consisting of two bytes in the pin MOSI.
The bit9 through bit15 is an address. 1010101.
You can enable or disable the VKAM. Lets say you will disable it. Bit7 will be 0, bit6 0, bit5 must be 1 to go to LPOFF mode, bit 4 will be 0.
The lowest four bits must be set according the section 7.2.6 in the datasheet.
Bit3=NOT(Bit5)=0
Bit2=NOT(Bit4)=1
Bit1=Bit7=0
Bit0=Bit6=0
The 2 bytes will be 1010101P 00100100
The P is the Parity bit, which should be calculated according the section 7.1.2 in the datasheet.
Because the number of 1 in the bits 15–9, 7–0 sequence is even in this case, the Parity bit will be 1.
So the final 2 bytes will be 10101011 00100100=0xAB24.
Please note, that the NCS (Not chip select) must be low for the transmission.
With Best Regards,
Jozef
