Part Number:BQ27GDK000EVM
I had an issue with the BQ27GDK000EVM and received the more detailed schematic in PDF form. After probing the test points I found that the output of the 4.096V voltage reference chip U4 was only 2.596. I replaced U4 with a new REF3240 and the output was still 2.596. I though maybe the DAC8560 (U10) was damaged and replaced it with a new DAC8560 but again the voltage was 2.596. After probing the TP49, TP68 and TP69 I found that CS_DAC and GDK_SCLK signals looked good but the GDK_SIMO was toggling very slowly between 0 and 1.44 volts. I believe the MSP430 is not communicating with the DAC8560 chip and the internal 2.5 voltage reference is enabled which is the default state. This is why the reference voltage is measuring 2.596 volts. I am not sure if the MSP430 is damaged or what is causing the GDK_SIMO signal to be incorrect so I ordered a second BQ27GDK000EVM.
With the second BQ27GDK000EVM I ran the GDK script for the learning cycle using the new GDK board but the process does not complete sucessfully. Initially the discharge stage ended with the status message "End Task (Unexpected): Discharge - false". I changed the discharge rate in the script from DCby5 to DCby10 with DESIGN_CAP defined as 4800. After this change the discharge completed but now the charge stage exits with the status message "End Task (Unexpected): Charge - false". I did have bqStudio recording the log of the but the only thing that changes is the current measurements. The status registers and flags do not change at the point where the End Task occurs. It appears that these events happen at or very close to the termination point. For example the "End Task (Unexpected): Dischage - false" would occur very near the point where the battery voltage reached the TERMINATE_VOLTAGE 3000. The "End Task (Unexpected): Charge - false" would occur very near the point where the taper current reached TAPER_CURRENT which is defined as 100. The EV2400 firmware is 0.18 and I am not sure what the firmware version is in the GDK section. I downloaded a version GDKFW_V1_06_INA220.txt I found linked on these forums. I had installed that verison on the first GDK board but have not installed it on the second. I am worried that possibly the firmware might have caused the issue on the first GDK board. It is possible that the GDK could be causing the unexpected condition? Alternatively is there something in the BQ27530-G1 data memory (flash) that would cause a fault and result in the GDK ending the task. I tried to adjust the Terminate Voltage and the Final Voltage but I still get the "Unexpected" message when the task reaches the TERMINATE_VOLTAGE in the GDK script. It does not seem to matter if I set TERMINATE_VOLTAGE to 3000 mV or 3200 mV the "Unexpected" event happens when the measured voltage reaches this point.
