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7.1 Board Specific SEMA Functions
7.1.1 Voltages
The BMC of the ETX-BT implements a voltage monitor and samples several onboard
voltages. The voltages can be read by calling the SEMA function “Get Voltages”. The
function returns a 16-bit value divided into high-byte (MSB) and low-byte (LSB).
ADC
Channel
Voltage Name
Voltage Formula [V]
0
CPU-Vcore
(MSB<<8 + LSB) x 3.3 / 1024
1
GFX-Vcore
(MSB<<8 + LSB) x 3.3 / 1024
2
+V1.05S
(MSB<<8 + LSB) x 3.3 / 1024
3
Vmem
(MSB<<8 + LSB) x 3.3 / 1024
4
+V1.0V
(MSB<<8 + LSB) x 3.3 / 1024
5
+V3.3V
(MSB<<8 + LSB) x 1.1 x 3.3 / 1024
6 +VIN (MSB<<8 + LSB) x 6.000 x 3.3 /
1024
7
MAIN CURRENT
Use Main Current Function
7.1.2 Main
Current
The BMC of the ETX-BT implements a current monitor. The current can be read by calling
the SEMA function “Get Main Current”. The function returns four 16-bit values divided in
high-byte (MSB) and low-byte (LSB). These 4 values represent the last 4 currents drawn
by the board. The values are sampled every 250ms. The order of the 4 values is NOT in
chronological order. Access by the BMC may increase the drawn current of the whole
system. In this case, there are still 3 samples not influenced by the read access.
Main Current = (MSB_n<<8 + LSB_n) x 8.06mA
