When working with the AD9361 I noticed that GPO 0 comes up in a "1" (logic high) state before initialization.
Do all the GPOs come up in state 1 (logic high) before initialization? Is there any GPOs that come up in a logic low before initialization?
In order to establish voltage lever at GPO pins after reset You have to refer to AD9361 register map.
First you should check register address 0x26. Default value of that register is 0x00. Witch those settings GPO manual select (Reg26 bit 4) = 0. That means GPOs slave to the ENSM and, depending on the settings in register 0x020, may change state as the ENSM changes state.
Default value for Register 0x20 = 0x33
- that means GPO1 and GPO0 are following ENSM.
Since default value in register 0x27 = 0x03
- in ALERT state the GPO1 and GPO0 = 1
- in Tx and in Rx mode GPO1 and GPO0 = 0
- in SLEEP and WAIT state GPO1 and GPO0 = 0
With default values GPO3 and GPO2 = 0 all the time.
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