Posted on January 15, 2014 at 10:19 Hi,
I'm trying to communicate between the
http://www.ti.com/product/ADS7870
and the ST microcontroller STM32F4 Discovery evaluation board. I'm using IAR and at the moment I'm just trying to read register 31 from the ADC (which should return a 1) but with no luck.
I'm setting the SPI on the microcontrontroller as follows: data transmitted as MSB first, clock low in idle state, data is captured on rising edge, data size is 8 bits, and full duplex transmission.
In main.c I do:
http://e2e.ti.com/support/data_converters/precision_data_converters/f/73/t/3147aspx#
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debug = ads7870Init();
if
(debug==1)
printf
(
''adc is alive \n''
);
else
printf
(
''adc is DEAD \n''
);
And in
http://www.ti.com/product/ads7870
_driver.c I have:
http://e2e.ti.com/support/data_converters/precision_data_converters/f/73/t/3147aspx#
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//initialize ADC
uint8_t ads7870Init(
void
)
{
//// check ID register
if
(ads7870ReadReg(ADS7870_ID) != ADS7870_ID_VALUE)
return
0;
else
{
//// setup reference and buffer
ads7870WriteReg(ADS7870_REFOSC, ADS7870_REFOSC_OSCE | ADS7870_REFOSC_REFE | ADS7870_REFOSC_BUFE);
//// return success
return
1;
}
}
I'm attaching a screenshot of what I see on the scope. (yellow: sclk, blue: read command register 31, purple: output from ADC).
http://e2e.ti.com/cfs-file.ashx/__key/communityserver-discussions-components-files/73/67stm32f4_5F00_response_5F00_scope.PNG
MOSI transmits properly to the
http://www.ti.com/product/ADS7870
(the din pin receives read command), but there is no response coming from the ADC dout pin.
I would really appreciate any help on this.
Thank you.
