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8,464 Views
Registered: ‎06-29-2015

Incorrect register Reset Value

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I was debugging a UART baud rate problem on a new Zynq7000 board and found the problem was an incorrect reset value for Baud_rate_divider_reg for UART1.

 

The code did not change the value from expected reset value which caused my problem.

 

What could cause the register to not have the correct reset value?  

 

The datasheet specifies that it should have a reset value of 0xF.  When I read at uart 0 baud_rate_divider_reg at 0xE0000034, then I get 0xF, but when I read uart 1 baud_rate_diver_reg at 0xE0001034, then I get 0x6.  I get this on two boards (both new designs), so it looks like a design problem.

 

I've used XMD to ensure that no scripts are running after reset.  This is the value of the reset when doing a mrd after rst.

 

I've checked that all my power supplies ramp up within the specified time and with the correct sequencing.  CPU_POR_B is connect to POWER_GOOD of my 1V power supply.

 

I am worried that this may be a symptom of a larger problem, and if one register is not initialized correclty, then there may be more.

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15,744 Views
Registered: ‎06-29-2015

Re: Incorrect register Reset Value

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This is not a problem, but normal operation.  The register reset values are changed by the BootROM code.  See Table 6-22 in UG585 for register values after BootROM execution.

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15,745 Views
Registered: ‎06-29-2015

Re: Incorrect register Reset Value

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This is not a problem, but normal operation.  The register reset values are changed by the BootROM code.  See Table 6-22 in UG585 for register values after BootROM execution.

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