kender
Advanced Member level 4
Colleagues,
Wrote a small program in IAR EWARM to test SPI. It runs, but SCLK and MOSI do not show up on the oscilloscope. Here’s the code, which actually makes SPI transactions:
With a scope, I can see the LD# line toggle up and down, so this program doesn’t hang while polling for SPIF. Rang-out the wiring - it seems to be correct. Nothing is shorted to Vcc or GND. Added a pullup and enabled SSEL in PINSEL3, following this advice: **broken link removed**. Checked that PINSEL doesn’t get overwritten. But still no clock.
Here’s the initialization of my SPI peripheral:
Can you spot any errors? What else can I check?
Thanks,
- Nick
Wrote a small program in IAR EWARM to test SPI. It runs, but SCLK and MOSI do not show up on the oscilloscope. Here’s the code, which actually makes SPI transactions:
Code:
while(1)
{
S0SPCCR = 32; // SCLK rate
S0SPCR =
0x00000000 | // MOSI valid on raising edge of SCLK (CPOL=CPHA=0)
0x00000020 | // master (AD7390 DAC is the slave)
0x00000000 | // MSbit first
0x00000000 | // SPI interrupt inhibited
0x000C0004; // transmit 12 bits (BitEnable, BITS)
DAC_xLD_FSET = DAC_xLD_MASK; // drive LD# high
S0SPDR = 0x7FF; // write to the data register (this will start the transmission and clear the SPIF bit)
while ( !(S0SPSR & 0x80) ); // poll SPIF bit for the end of transaction
DAC_xLD_FCLR = DAC_xLD_MASK; // drive LD# low (data gets written from serial shift register to DAC register)
}Here’s the initialization of my SPI peripheral:
Code:
void SPI_Init()
{
PCONP_bit.PCSPI = 1;
PINSEL3 = 0x0003CF00;
}Thanks,
- Nick