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CS Series Voltage Adjustment

Overview

The CSOT CS602 and CS603 series PMICs differ from standard PMICs — they do not have internal non-volatile memory. These PMICs work as follows: on each power-up, the TCON board's main controller sends configuration data over I2C to initialize the chip.

Therefore, adjusting voltage parameters on CS-series PMICs essentially means modifying the firmware data in the external QSPI Flash on the TCON board.

Supported Models

  • CS602
  • CS603

How It Works

The CS-series PMIC workflow:

TCON board powers up → Main controller reads external QSPI Flash → Configures CS602/CS603 via I2C → PMIC outputs preset voltages

Since the configuration data originates from the TCON board's Flash, voltage adjustment requires:

  1. Reading the QSPI Flash content from the TCON board
  2. Parsing the PMIC configuration data section
  3. Modifying the target voltage parameters
  4. Writing the modified data back to Flash

Operation

Read Flash Firmware

  1. Select CS Series from the main menu
  2. Connect to the SPI Flash chip on the TCON board:
  3. SOP8 Probe Clip: Clip onto the Flash chip pins without desoldering — ideal for quick testing
  4. IC Locking Socket (Programmer Socket): Place the Flash chip into the locking socket — suitable for offline programming or when the chip has already been removed
  5. Choose Read Flash — the tool automatically reads the entire Flash content
  6. PMIC configuration parameters are parsed and displayed

Modify Parameters

  1. Rotate the encoder to select the voltage channel (VGH / VGL / VCOM, etc.)
  2. Press the encoder to enter edit mode
  3. Adjust the target voltage value
  4. Confirm the modification

Write Firmware

  1. After modification, select Write Flash
  2. The tool writes the modified firmware back to the TCON board's QSPI Flash
  3. Automatic verification follows the write operation

Verification

  • Power-cycle the TCON board — the PMIC will initialize with the new parameters
  • Use a multimeter to confirm the output voltages

Limitations

This method does NOT apply in the following scenarios:

  • TCON boards without a main controller (e.g., driven directly by the monitor's SoC)
  • PMIC configuration data stored inside the mainboard's EMMC with no dedicated Flash on the TCON board

Precautions

  • Confirm the TCON board's Flash chip model and correct wiring before operation
  • Back up the original firmware to the tool's external Flash after reading
  • Write operations carry risk — incorrect modifications may render the logic board inoperable
  • Ensure stable power supply — do not power off during the write process

Probe Usage Notes

On some TCON boards, when using an SOP8 probe clip to read/write the Flash, the probe's 3.3V supply may power up the TCON main controller. The main controller will then occupy the SPI bus to communicate with the Flash, preventing the tool from connecting properly. In this case, the tool will display "Device not connected" or "Device not adapted."

Solution: Desolder the Flash chip from the TCON board and use the IC locking socket (programmer socket) for offline programming.

Interface Usage Notes

  • Do not connect the probe while the tool is plugged into the 4K interface, as the 4K interface outputs 12V during read operations, which will also power up the TCON main controller and interfere with SPI communication.
  • If the above conditions have been ruled out but the tool still shows "Device not adapted," please contact the developer for chip adaptation support.