[USRP-users] ATR registers

Ian Buckley ianb at ionconcepts.com
Thu Oct 9 15:49:46 EDT 2014

Recent versions of UHD include the example uhd/host/examples/fpgpio.cpp (for X300) which gives an example of writing ATR code.


On Oct 9, 2014, at 11:29 AM, Per Zetterberg <perz at kth.se> wrote:

> Thank you for your answer Ian!
> I know I had the same setting for IDLE and RX. I do have a  set_pin_ctrl call. I tried DDR also but my understanding is that it shouldn't matter for ATR but only for GPIO.
> Thanks again,
> Per 
> ________________________________________
> From: Ian Buckley [ianb at ionconcepts.com]
> Sent: Thursday, October 09, 2014 7:50 PM
> To: Per Zetterberg
> Cc: usrp-users at lists.ettus.com
> Subject: Re: [USRP-users] ATR registers
> Per,
> A couple of quick observations.
> 1) The example you present below writes both the IDLE state and RX state with the same values (atr_rx) so you would not see a transition of GPIO pins between those states.
> 2) You haven't shown a configuration write ti the DDR register which is defined as:
> The CTRL reg determines whether the GPIO is driven by internal state changes in the radio streaming control logic or if it just works like traditional bit-banged GPIO. 0=Manual mode 1=ATR
> The DDR reg (data direction register) sets port direction…where a 1 is an output, 0 is an input
> The OUT reg controls the bit values driven on output configured GPIOs.
> Hope this helps
> -Ian
> On Oct 9, 2014, at 4:31 AM, Per Zetterberg via USRP-users <usrp-users at lists.ettus.com> wrote:
>> Dear List,
>> I am trying to use the ATR registers with a basic daughterboard. I do:
>> db_iface->set_pin_ctrl(m_unit,mask_write,mask_write);
>> db_iface->set_atr_reg(m_unit,
>>                 uhd::usrp::dboard_iface::ATR_REG_IDLE,atr_rx,mask_write);
>>   db_iface->set_atr_reg(m_unit,
>>                 uhd::usrp::dboard_iface::ATR_REG_TX_ONLY,atr_tx,mask_write);
>>   db_iface->set_atr_reg(m_unit,
>>                 uhd::usrp::dboard_iface::ATR_REG_RX_ONLY,atr_rx,mask_write);
>> Upon writing these values the settings of ATR_REG_IDLE should immediately take effect until we ask the USRP to send or receive samples. But this does not seem to be the case. Am I making a mistake?
>> BR/
>> Per
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