Tool/software:
Hello. I have written an I2C script to program an on-board TPS53861. All the values hold, except VOUT_COMMAND is reset to default 0x0033 value after I execute the STORE_DEFAULT_ALL command. I set 10mV step mode, and then assign 0.8V to Rail A by writing 0x001F to the VOUT_COMMAND (0x21) register. This works correctly until I run STORE_DEFAULT_ALL, which resets VOUT_COMMAND to default value. Is there some security mechanism I am missing?
Please see the programming script I wrote below:
#!/bin/sh
bus=3
device=0x60
check_device() {
if ! i2cdetect -y $bus | grep -q "${device#0x}"; then
echo "Error: Device $device not found on I2C bus $bus"
exit 1
fi
echo "TPS53861 device found on I2C bus $bus"
}
i2c_write() {
local register=$1
local value=$2
local mode=$3
i2cset -y $bus $device $register $value $mode
}
i2c_read() {
local register=$1
local mode=$2
i2cget -y $bus $device $register $mode | tr 'A-Z' 'a-z'
}
store_custom_defaults() {
echo "Disabling write protect..."
i2c_write 0x10 0x00 b
write_protect=$(i2c_read 0x10 b)
if [ "$write_protect" != "0x00" ]; then
echo "Error: Failed to disable write protect"
exit 1
fi
echo "Storing current configuration to NVM..."
i2c_write 0x11 # STORE_USER_ALL - dataless send byte transaction
# wait for NVM store (500ms minimum for EEPROM write)
sleep 0.5
status=$(i2c_read 0x7E b) # Check STATUS_CML register
if [ $((status & 0x08)) -ne 0 ]; then
echo "Error: Memory write operation failed"
exit 1
fi
echo "Re-enabling write protect..."
i2c_write 0x10 0x80 b
echo "Custom configuration stored successfully as NVM defaults"
echo "Power cycle the device for the changes to take effect"
}
echo "Entering TPS53861 program..."
check_device
printf "Do you want to continue? (y/n): "
read response
case $response in
[Yy]*)
;;
*)
echo "Exit."
exit 1
;;
esac
echo "Configuring TPS53681 PMIC..."
i2c_write 0x00 0x00 b # Set PAGE to 0 for Rail A
# Set dynamic phase shedding (DSP_EN)
echo "Enabling dynamic phase shedding..."
i2c_write 0xDE 0x85 w
# Set maximum output current (IOUT_MAX)
echo "Setting maximum output current for Rail A to 185A..."
i2c_write 0xDA 0xC8B9 w
# Set over-current fault threshold (IOUT_OC_FAULT_LIMIT)
echo "Setting over-current protection threshold for Rail A to 278A..."
i2c_write 0x46 0x0116 w
# Set over-current warning threshold (IOUT_OC_WARN_LIMIT)
echo "Setting over-current warning threshold for Rail A to 185A..."
i2c_write 0x4A 0x00B9 w
# Read current MFR_SPECIFIC_13 value
mfr_specific_13=$(i2c_read 0xDD w)
# Only modify bits 7:5 in the lower byte, preserve upper byte
new_value=$(( ($mfr_specific_13 & 0xFF1F) | 0x0080 ))
i2c_write 0xDD $new_value w
status_cml_pre=$(i2c_read 0x7E b)
echo "STATUS_CML before: 0x$(printf '%02x' $status_cml_pre)"
verify_value=$(i2c_read 0xDD w)
echo "MFR_SPECIFIC_13 before: 0x$(printf '%04x' $mfr_specific_13)"
echo "MFR_SPECIFIC_13 after: 0x$(printf '%04x' $verify_value)"
status_cml_post=$(i2c_read 0x7E b)
echo "STATUS_CML after: 0x$(printf '%02x' $status_cml_post)"
echo "Ensure VID_MODE DAC resolution"
vid_mode=$(i2c_read 0x20 b)
if [ "$vid_mode" != "0x21" ]; then
echo "VID mode changed from defaults! Got $vid_mode"
else
echo "VID mode is default, 5mV DAC resolution"
fi
# Set VOUT_COMMAND for Rail A to 0.8V -- default 0, so no need to set PAGE register
echo "Setting VOUT_COMMAND for Rail A to 0.8V..."
#i2c_write 0x21 0x6F w
i2c_write 0x21 0x001F w
# Set ON_OFF_CONFIG to be enabled by AVR_EN (ON_OFF_CONFIG)
echo "Setting ON_OFF_CONFIG fo Rail A to be enabled by AVR_EN"
i2c_write 0x02 0x17
# Enable Rail A
#echo "Enabling Rail A..."
#i2c_write 0x01 0x80 b
# Disable Rail B
echo "Disabling Rail B..."
i2c_write 0x00 0x01 b # Set PAGE to 1
i2c_write 0x01 0x00 b # Set OPERATION to off
echo "Verifying settings..."
page_value=$(i2c_read 0x00 b)
if [ "$page_value" != "0x01" ]; then
echo "Error: PAGE register verification failed. Expected 0x01, got $page_value"
exit 1
fi
rail_b_value=$(i2c_read 0x01 b)
if [ "$rail_b_value" != "0x00" ]; then
echo "Error: Rail B verification failed. Expected 0x00, got $rail_b_value"
exit 1
fi
# Set back to PAGE 0
i2c_write 0x00 0x00 b
#rail_a_value=$(i2c_read 0x01 b)
#if [ "$rail_a_value" != "0x80" ]; then
# echo "Error: Rail A verification failed. Expected 0x80, got $rail_a_value"
# exit 1
#fi
# All following values in PAGE 0 (RAIL A)
vout_value=$(i2c_read 0x21 w)
if [ "$vout_value" != "0x001f" ]; then
echo "Error: VOUT_COMMAND verification failed. Expected 0x001f, got $vout_value"
exit 1
fi
dsp_value=$(i2c_read 0xDE w)
if [ "$dsp_value" != "0x0085" ]; then
echo "Error: DSP_EN verification failed. Expected 0x0085, got $dsp_value"
exit 1
fi
vout_value=$(i2c_read 0xDA w)
if [ "$vout_value" != "0xc8b9" ]; then
echo "Error: IOUT_MAX verification failed. Expected 0xc8b9, got $vout_value"
exit 1
fi
fault_value=$(i2c_read 0x46 w)
if [ "$fault_value" != "0x0116" ]; then
echo "Error: IOUT_OC_FAULT_LIMIT verification failed. Expected 0x0116, got $fault_value"
exit 1
fi
warn_value=$(i2c_read 0x4A w)
if [ "$warn_value" != "0x00b9" ]; then
echo "Error: IOUT_OC_WARN_LIMIT verification failed. Expected 0x00b9, got $warn_value"
exit 1
fi
on_off_config=$(i2c_read 0x02 b)
if [ "$on_off_config" != "0x17" ]; then
echo "Error: ON_OFF_CONFIG verification failed. Expected 0x17, got $on_off_config"
exit 1
fi
store_custom_defaults
echo "TPS53861 programming complete"
