Hi...I am pretty new in stm32 world and this is my problem:
Context of the problem
I am transmitting data from a computer to the STM32F446ET through the USB port.
The string the PC sends is:
cadena = ["1","0","0","0","3","0","0","0","0","1","7","2","8","C","0","0","0","0","0","0","0","0","0","0"]
it is a simple string of 24 characters representing hex values.
The microcontroller receives the string and storage it in a union of structures as follows:
union datos
{
uint8_t imun[24]; //This is the vector where the mcu receives the chain.
struct
{
uint8_t hatsof; // start/stop
uint8_t dirx; //direction in x
uint8_t diry; //direction in y
uint8_t dirz; //direction in z
uint32_t prsc; //prescaler value
uint32_t arrd; //Auto-reload register value
uint32_t x; //distance in x
uint32_t y; //distance in y
uint32_t z; //distance in z
};
struct
{
uint8_t hatsofa; //Start/stop byte
uint8_t dirxa; //x direction byte
uint8_t dirya; //y direction byte
uint8_t dirza; //z direction byte
uint8_t prsca; //prescaler byte 1
uint8_t prscb; //prescaler byte 2
uint8_t prscc; //prescaler byte 3
uint8_t prscd; //prescaler byte 4
uint8_t arrda; //auto-reload byte 1
uint8_t arrdb; //auto-reload byte 2
uint8_t arrdc; //auto-reload byte 3
uint8_t arrdd; //auto-reload byte 4
uint8_t xa; //x distance byte 1
uint8_t xb; //x distance byte 2
uint8_t xc; //x distance byte 3
uint8_t xd; //x distance byte 4
uint8_t ya; //y distance byte 1
uint8_t yb; //y distance byte 2
uint8_t yc; //y distance byte 3
uint8_t yd; //y distance byte 4
uint8_t za; //z distance byte 1
uint8_t zb; //z distance byte 2
uint8_t zc; //z distance byte 3
uint8_t zd; //z distance byte 4
};
}u1;
Then I need to transform everything from hex string to hex values. I do it through this function:
void transforma2(void)
{
int i = 0;
// Here, each ascii value is changed to a numerical value:
for (i=0;i<24;i++)
{
if (u1.imun[i]<58)
u1.imun[i] = u1.imun[i] - 48;
else
u1.imun[i] = u1.imun[i] - 55;
}
// then each byte is used to be transformed into a numerical value:
u1.prsc = u1.prsca + u1.prscb*16 + u1.prscc*256 + u1.prscd*4096; //Prescaler value
u1.arrd = u1.arrda + u1.arrdb*16 + u1.arrdc*256 + u1.arrdd*4096; //Auto-reload value
u1.x = u1.xa + u1.xb*16 + u1.xc*256 + u1.xd*4096; // x value
u1.y = u1.ya + u1.yb*16 + u1.yc*256 + u1.yd*4096; // y value
u1.z = u1.za + u1.zb*16 + u1.zc*256 + u1.zd*4096; // z value
}
The problem:
The serial string received is right, the union contains the information according to what is expected and the function transform the information but just the 2 first times the function is called, the 3rd time everything gets messed up...
Can anyone help me?? Maybe I am not considering something....why could it work fine the first 2 times but and not anymore??
Note: the 3rd time and so on, when it is debugged, works fine...but running does not work... I do not understand.
