Dear Sir or Madam,
I have a problem of SPI communication(4-wire) with ARM core processor(Cortex-M3).
I think my circuit schematic is almost same with AD9548 Evaluation Board's schematic.
I'm trying to write/read with AD9548's registers.
My configurtion is as follows.
1. M0/M1/M2 pins = 0(GND)
2. SCLK/SCL(AD9548) - SCLK(ARM), SDIO(AD9548)-MOSI(ARM), SDO(AD9548)-MISO(ARM), CSB/SDA(AD9548)-CS(ARM)
3. All lines of SPI are pull-up(4.7K)
4. W1/W0 = 0(1 byte to transfer)
with this conditions.
after power-on, I tried to write 0x80 to 0x0000 register(sireal configuration, only 4-wire bit enable)
and then when I read a 0x0002 and 0x0003 register(silicon revision level & Device ID), the results are always 0xff.
what does it wrong?