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en:arm:tqma7x:linux:ptxdist:known_issues [2018/05/22 11:17] – changed template + added labels build_system and build_system_head liedmann | en:arm:tqma7x:linux:ptxdist:known_issues [2018/06/13 13:37] – added RS485 issue liedmann |
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===== MBa7x ====== | ===== MBa57x ====== |
==== RS485 ==== | ==== RS485 ==== |
^ RS485 bus block in half-duplex mode ^^ | ^ RS485 bus block in half-duplex mode ^^ |
^ Affects | RS485 via UARTx | | ^ Affects | RS485 via UARTx on MBa57xx Revsion 01xx | |
^ Issue | During i.MX7 reset the UARTx.CTS# pin is low by default (CPU internal pull down) | | ^ Issue | During AM57xx reset the UARTx.CTS# pin is low by default (CPU internal pull down) | |
^ Effect | Using the MBa7x RS485 circuitry in a half-duplex slave device or half-duplex multi-master environment may block the RS485 bus during i.MX7 reset.\\ The bus is released as soon as the UARTx.CTS# pin is properly configured by software (e.g. U-Boot, Linux, etc.) | | ^ Effect | Using the AM57xx RS485 circuitry in a half-duplex slave device or half-duplex multi-master environment may block the RS485 bus during AM57xx reset.\\ The bus is released as soon as the UARTx.CTS# pin is properly configured by software (e.g. U-Boot, Linux, etc.) | |
^ Solution / Workaround | Add a 10k pull up to the UARTx.CTS# signal on carrier board | | ^ Solution / Workaround | Add a 10k pull up to the UARTx.CTS# signal on carrier board \\ This behaviour will be fixed with MBa57xx REV.02xx | |
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