LTC4332 local SPI interface can not be connected with MCU

Question

One piece ltc4332 is used in local mode , and communicate with Mcu using SPI bus, no MISO signal is emitted from local LTC4332. The connection of the circuit is according to page 22 of the datasheet, d o not know this is what reason? Can someone give me a hand?

ericb · Accepted Answer

Will need more details about how you're hooking things up to be able to know why things aren't working. Things to check include: 
 
 Local and remote LTC4332's have proper power supplies for Vcc and VL 
 The link cables are properly connected 
 The local LTC4332's remote pin is pulled low and the remote LTC4332's remote pin is pulled to VL 
 The local/remote SPEEDx configurations match and the SPEEDx speed is equal or greater to the local SCK 
 if not present, add the LED's to the nLINK pins and confirm both are lit (nLINK is pulled low). 
 you are only asserting one nSSx pin at a time,
 
 use nSSC to talk with the local LTC4332 target device (internal config) 
 use nSS1 - nSS3 to talk to the remote device using nSS1 - nSS3

confirm that your MCU can correctly talk to the remote device so you know the MCU SPI is working correctly.
 
 note that the MCU software needs to change based on if the extender link is present or not. If the extender is present, then the extra dummy SPI read needs to be included.

Eric

Electronic Design Services - PartnerZone

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LTC4332 local SPI interface can not be connected with MCU

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