I'm new to nrf8001 I'm trying to understand an existing example. in this example after sending set up commands generated by nrfgo studio , program sends 9 byte of 0xff command (invalid aci command) , waits for 20 ms and then send 4 byte of that again. why is this happening!?
void setup (void) {
int m,j;
unsigned char temp[10],k;
for(m=0;m<NB_SETUP_MESSAGES;m++) {
REQN = 0;
while (RDYN == 1);
k=setup_line[m][0];
spi(k);
for (j=1;j<=k;j++)
{
spi(setup_line[m][j]);
}
REQN=1;
while(RDYN==0);
delay_ms(20); }
REQN=0;
while(RDYN==1);
spi(ACI_CMD_INVALID);
spi(ACI_CMD_INVALID);
spi(ACI_CMD_INVALID);
spi(ACI_CMD_INVALID);
spi(ACI_CMD_INVALID);
spi(ACI_CMD_INVALID);
spi(ACI_CMD_INVALID);
spi(ACI_CMD_INVALID);
spi(ACI_CMD_INVALID);
REQN=1;
while(RDYN==0);
delay_ms(20);
REQN=0;
while(RDYN==1);
spi(ACI_CMD_INVALID);
spi(ACI_CMD_INVALID);
spi(ACI_CMD_INVALID);
spi(ACI_CMD_INVALID);
switch(SPDR) //SPDR = spi return value
{
case 1:
putsf("Device started in TEST mode. \n");
break;
case 2:
putsf("Device started in SETUP mode. \n");
break;
case 3:
putsf("Device started in STANDBY mode. \n");
break;
default:
putsf("Something goes WRONG!!! \n");
break; };
spi(ACI_CMD_INVALID);
sprintf(temp,"Number of errors = %d \n",SPDR);
puts(temp);
spi(ACI_CMD_INVALID);
sprintf(temp,"Number of dataCommand buffers = %d \n",SPDR);
puts(temp);
REQN = 1;
delay_ms(60);
while (RDYN == 0); }
here is my bluetooth set up code. the ACI_CMD_INVALID contains 0xff value. I don't understand the need for this invalid opcode
