Software Description: Monitoring Of Up To 12 Battery Cells - Atmel ATmega32HVB User Manual

4.

Software Description: Monitoring of Up to 12 Battery Cells

The supplied code is documented and easy to adjust for verifying the functions of the Atmel
application development work.
After the board has been connected as described above the microcontroller automatically starts a cyclic measurement of
voltages, temperature, and current. LED 1 indicates these cyclic measurements. It toggles in default operation. A
continuously illuminated LED1 indicates an open clamp. See
about open clamp detection. LED 2 indicates that for some reason the MOSFETS have been disabled. The default software
disables the FETs in case of these events:
●
Overvoltage (at least 1 cell exceeds the upper default threshold of 4.2V)
●
Undervoltage (at least 1 cell exceeds the lower default threshold of 2.5V)
●
Overcurrent (the current through the shunt exceeds the default threshold of 80mA)
●
Overheating (the temperature exceeds the upper threshold, default value is 60°C)
●
Low temperature threshold (the default threshold is -20°C)
LED 3 indicates whether the Atmel ATA6870s are turned on or not. An active LED indicates that the Atmel ATA6870s are
enabled.
Table 4-1. LED Functions
LED
LED 1
LED 2
LED 3
The Atmel ATmega32HVB has no clock divider to provide an external slower clock than 1/2 CPU clock. Requirement of
Atmel ATA6870 is f
of the Atmel ATA6870 and 250kHz for SPI.
6 ATA6870-DK10 [APPLICATION NOTE]
9228C–AUTO–02/15
Function
Indicates clamp is open when permanently illuminated
Indicates cyclic measurements when blinking
On indicates disabled MOSFETs for one of the reasons listed above
On indicates active Atmel ATA6870
> 2 f
. Hence, the clock frequency of 1MHz is mandatory to provide a 500kHz clock for the ADCs
CLK SPI
Section 4.2 "Open Cell Check" on page 7
®
ATA6870 and start BMS
for more information