AD5111 Writing issue

Question

Hello, 
 One of my customers is using the AD5111 digital potenziometer. 
 He has an issue with writing to his egisters 
 Their tining is according to the figure 3 in the data sheet 
 The CS is tied to "low" by pull down. During this cycle the CLK is in HIGH 
 The writing cycle is failed whther they start the U/D# pin from "HIGH" as follows: HIGH-LOW-HIGH-LOW - then the EEPROM programm is not succeeds. 
 Using the following U/D# cycle the EEPROM programm is performed successfully: LOW-HIGH-LOW . 
 I can't see any limitations for it in data sheet. 
 Do you have any idea why during the HIGH-LOW-HIGH-LOW cycle the writing to the eeprom is failed? 
 Thanks 
 Meir

ADIApproved · Accepted Answer

Hi Meir, 
 The EEPROM will only be stored on a positive pulse. LOW-HIGH-LOW 
 Other than the EEPROM command, the datasheet states that the U/D line should be changed while CLK is LOW (see the basic operation section of the datasheet) 
 Please advise the customer to have their U/D line LOW before attempting to program the EEPROM. 
 Or in other words, use the LOW-HIGH-LOW method. 
 Kind Regards, 
 David)

Electronic Design Services - PartnerZone

Products Mentioned

AD5111 Writing issue