[En-Nut-Discussion] SPIBUS and PullUp and testing Miso line.
bon at elektron.ikp.physik.tu-darmstadt.de
Thu Aug 28 14:52:18 CEST 2014
>>>>> "Ole" == Ole Reinhardt <ole.reinhardt at embedded-it.de> writes:
Ole> Hi Uwe, Am 26.08.2014 16:55, schrieb Uwe Bonnes:
>> to see if the ADC is ready, for SPI Sigma Delta ADC from Linear
>> Technology like the LTC2484, one has to select the device, apply a
>> pullup to SDI and query the SDI pin without toggling SCK. Only if SDI
>> is low, data is available. - Is it OK to add SPI_MODE_PULLUP
>> properity in include/dev/spibus.h? - Is it worth to add a method to
>> query the Miso pin? I would implement handling of those mode bits
>> and function in STM32 and GPIO. However I can also circumvent the
>> driver and use GPIO Functions directly...
Ole> I never heard of such a requirement, but do you have a clue, if
Ole> this is a standard?
Standard asr fine, so everybody has it's own standards. But at least the
Analog devices AD7982 in "CS MODE, 3-WIRE WITH BUSY INDICATOR" has also SDO
floating while busy and pulled low when ready.
Ole> In this case we should add it to the driver, but I assume it is a
Ole> very special case for these ADCs, so a solution implemented with
Ole> the GPIO functions would be better in my eyes.
Probably it's not worth to abstract those things...
Uwe Bonnes bon at elektron.ikp.physik.tu-darmstadt.de
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
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