cExpress-BL
Page 39
5.1.
Board Specific SEMA Functions
5.1.1.
Voltages
The BMC of the cExpress-BL 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
+V1.5S
(MSB<<8 + LSB) x 3.3 / 1024
1
+VCORE
(MSB<<8 + LSB) x 3.3 / 1024
2
+V1.05S
(MSB<<8 + LSB) x 3.3 / 1024
3
+V3.3A
(MSB<<8 + LSB) x 1.100 x 3.3 / 1024
4
+VDDQ (V1.35 ~ V1.5)
(MSB<<8 + LSB) x 3.3 / 1024
5
+V5A_DUAL
(MSB<<8 + LSB) x 1.833 x 3.3 / 1024
6
+VIN
(MSB<<8 + LSB) x 6.000 x 3.3 / 1024
7
(MAIN CURRENT)
Use Main Current Function
5.1.2.
Main Current
The BMC of the cExpress-BL 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
5.1.3.
BMC Status
This register shows the status of BMC controlled signals on the cExpress-BL.
Status Bit
Signal
0 WDT_OUT
1 LVDS_VDDEN
2 LVDS_BKLTEN
3 BIOS_MODE
4 POSTWDT_DISn
5 SEL_BIOS
6 BIOS_DIS0n
7 BIOS_DIS1n
