Hi,
This is my first time to use DAC1220 EVM board to connect our own microcontroller through SPI interface, and I have some question for the startup sequences. I used the half-duplex SPI(mode 1,clk idle=0, the second edge to capture data ) for the serial interface, the frequency of SCLK is 125kHz. The DAC crystal is 2.45MHz, from the user guide, I connect microcontroller SPI sclk to DAC pin 3(SCLK); SPI MOSI to DAC pin 13(SDIO), GPIO pin (for CS) to DAC pin 7(CS) , the DAC pin 9(SDIEN). AVDD and DVDD connected 5V(the AVDD must to connect first), AGND and DGND connect to ground. S1 is turn right; S2 is turn down. Is any wrong wire to DAC1220?
And I write some command to the DAC. The figure 1 is for the reset pattern; Figure 2 is for write command to command register to set the DAC for 20-bit resolution (0x05,0xA1). Figure 2 is for the read the command register from DAC (0xc0, 0xff(dummy), 0xff(dummy)), but the SDIO always is zero. Have anyone have any recommendations for the setting to DAC1220? I'll be appreciate, thx.
Figure 1, the reset timing is 220us(high),13us(low),444us(high),13us(low),886us(high)
Figure 2
Figure 3