hi ,now im using the MC33908 SBC chip ,the problem i got is how to use the IO_0 to wake up the SBC, i use the following code make the SBC chip in a LPOFF state sucessfully ,but when i intend to wake up the SBC using IO_0 wake up , i failed , these is a very strange phenomenon, i can wake up the SBC for a very short time using rising edge of IO_0, but it can not last for good, i dont know why , anybody who is familiar with this chip can help me out? thanks a lot in advance.
//Put Can in sleep mode with no wakeup
// cmd = 0xB000;
// cmd = PwSBC_ComputeParity(cmd);
// status = PwSBC_SetMainReg(cmd); //Can enters sleep mode
cmd = 0xAA20;// LPOFF command according to datasheet
cmd = PwSBC_ComputeSecurityBits(cmd);
cmd = PwSBC_ComputeParity(cmd);
status = PwSBC_SetMainReg(cmd);// send command twice
status = PwSBC_SetMainReg(cmd);
G.w. Sun ,thanks for your reply sincerely.
1、 IGN signal is connected to 12V battery, IO_0 is configured to be awaken by rising edge
2、 the part schematic is just as picture shows
3、i read the document you uploaded carefully, it says before you enter LPOFF, need to make the SBC in a normal state, then a IO rising edge coming, the SBC back to power on again for good, is this how the wake-up function works?
datasheet not tell us what kind of state the SBC exactly is? when wake up happen ,does the SBC transfer from LPOFF state to normal state,or what else i should do further? and i need to emphasize that the SBC can be awaken but in a few second ,not totally can be wake up. the power indication light just flash one time, not light on all the time .
4、first , i initalize SBC Module, put it in normal state by configuration the register(INT), then put PwSBC_SleepMode in the end of the initalization program, so when i turn on power for circuit board , the SBC should be in a LPOFF state, then attach the IGN signal to 12V power supply, to simulate a rising edge of IO_0, but the power indication flash one time ,then all regulators power off ,just like it enter the LPOFF again, is there any logcial mistake ?
I do a test in EVB about the wake up function which you can refer to it.
Step below list:
1: power on EVB
2: Configure interrupt registers which including the wake up function ,at last configure INIT INT register enter normal mode.
3: Send SPI commend enter into sleep mode.
4: do a corresponding wake up operation which you have set in your setp2.