Hello, I want to share the external bus interfaces of a ST10F269 and a ST10F276 via the HLDEN-functionality. The pins are connected as follows: ST10F269 <=> ST10F276 D0..D15 <=> D0..D15 A0..A19 <=> A0..A19 /RD <=> /RD /WRL <=> /WRL /WRH <=> /WRH ALE <=> ALE /CS0../CS4 <=> /CS0../CS4 /BREQ <=> /HOLD /HLDA <=> /HLDA /HOLD <=> /BREQ The ST10F269 is configured as follows: - master (DP6.7 = 0) - HLDEN is set - XPERSHARE enabled - XRAM1 (E000-E7FF) enabled - XRAM2 (C000-DFFF) enabled The ST10F276 is configured as follows: - slave (DP6.7 = 1) - HLDEN is set - XPERSHARE disabled - XRAM1 (E000-E7FF) disabled - XRAM2 (F0000-FFFFF) enabled - BUSCON0: 16-Bit demux Now I want to access the master's XRAM (ST10F269) from the slave (ST10F276), /CS0 should get active for these bus accesses. Sometimes I can read correct data out of the master's XRAM, but sometimes I get wrong read data. It seems that bus conflicts occur. Maybe anyone can help me with the following questions: Is it necessary to also enable XPERSHARE in the slave? Is it necessary to enable VISIBLE? Are any waitstates needed for the XRAM access? If the slave (XPERSHARE disabled) accesses his own XRAM, is there also a HOLD-Request generated? Best regards, Michael