Hi all,
First time poster here, long time chip user.
I'm having some trouble getting my AD7738 to work (I do not have the eval kit).
I am not seeing anything on my DOUT. Below is an view of DOUT, DIN, RDY, and CS.
to configure it I am sending in
0x00, 0xFF, 0xFF, 0xFF, 0xFF to reset it and then
0x01 IO port register, write
0xF0 Configure IO port register
0x2F Channel setup register, AIN7, write
0x1C Configure Channel setup register
0x37 Channel conversion time register, AIN7, write
0x91 Std. value
0x3F Mode register, write (0x3F)
0x38 Continuous conversion, no clamp (0x38)
and then 0x4F every time RDY is polled.
but all I see is 0x00 in my rxbuffer, occasionally it goes 0xFF.
and the DOUT looks terrible. I'm at a loss.
my pin configurations are also
SCLK -> SCLK
MCLKIN -> CMOS CLK @ 12MHz
MCLKUT -> OPEN
CS -> SS
RESET -> 5V
AVdd -> 5V
AINCOM/P0 -> OPEN (is this correct?)
SYNC/p1 -> OPEN (is this correct?)
AIN0-AIN7 -> AIN7 connected to signal generator
MUXOUT(+) -> ADCIN(+)
MUXOUT(-) -> ADCIN(-)
REFIN(+) -> 2.5V (about.. actually 2.38V)
REFIN(-) -> GND
AGN -> GND
RDY -> ISR set to detect inverted rising edge and send out 0x4F
DOUT -> MISO
DIN -> MOSI
DVdd -> 5V
DGND -> GND
I attached a graph for my 0x4F polling and for my initial setup. the DOUT is sporadically working.. leading me to think I may have wired something wrong.
Even more confusing, half the time the rxBuffer ISR won't be triggered and other times it will.. with identical code.
Any help at all would be great. I am new to this chip and its kicking my **** and leaving me scratching my head.
thanks in advance,
scarlson
