AD5270 Command Operation

Question

Hello, 
 Our customer has troubled command operation of AD5270. They send the commands by following order and setting. 
 1) 0x2400 
 2) 0x1000 
 3) 0x1C02 
 4) 0x0400 
 After sending the commands, they checked the position of the digital rheostat wiper. The position was center. 
 Are there any problems in the order and/or setting of the commands? 
 And could you please advise me, why do we need an external pull-up resistor on SDO pin if it is not use? 
 Best regards, 
 Akira

musach · Accepted Answer

Hi Akira, 
 As the DS states, the only SPI mode supported by the AD5270 is CPOL = 0, CPHA = 1, and there is no way to change the mode. 
 You can check http://www.analog.com/media/cn/technical-documentation/application-notes/AN-1248.pdf if you are considering to use external components to operate the device in a different mode. 
 Regards, 
 Miguel