带摄像头 PMIC 的可扩展汽车 200 万像素摄像头模块参考设计 用于演示 DS90UB954-Q1 EVM 上的远程解串器的生产编程示例。本参考设计中使用的这种成像仪是 Onsemi® AR0233。该图像传感器需要的电源序列不同于默认 TPS65033000-Q1 序列，并且不允许 1.8V IO 电源轨首先上电。由于这是双板设计，在通过反向通道对 PMIC 进行重新编程期间，AR0233 图像板仅处于断开状态。

连接 DS90UB954-Q1 EVM 并为其通电后，本地 PC 可以运行脚本来配置反向通道并执行图 3-6 中的程序流。

import time# Set up IDs
UB954 = 0x60
UB953ID = 0x30
UB953 = 0x18
PMICID = 0xC0
PMIC = 0xC0

print "Configuring Back-Channel"

# Set up Port0
board.WriteI2C(UB954, 0x4C, 0x01)

# Set up Back Channel Config (0x58)
board.WriteI2C(UB954,0x58,0x5E)

# Set up SER ID
#board.WriteI2C(UB954,0x5B,UB953ID)
# Set up SER Alias ID
board.WriteI2C(UB954,0x5C,UB953)
# Set up Slave/PMIC ID
board.WriteI2C(UB954,0x5E,PMICID)
# Set up Slave/PMIC Alias ID
board.WriteI2C(UB954,0x66,PMIC)

time.sleep(0.1)

print "Reprogramming PMIC"

# Reprogram PMIC Power Sequence
board.WriteI2C(PMIC,0x02,0xDD)  # Unlock control registers
board.WriteI2C(PMIC,0x03,0x16)  # Disable Buck3 and LDO
board.WriteI2C(PMIC,0x04,0x1A)  # Disable the configuration CRC 
board.WriteI2C(PMIC,0x05,0xAA)  # Unlock configuration registers
board.WriteI2C(PMIC,0x0F,0x02)  # Reprogram power sequence
board.WriteI2C(PMIC,0x10,0x1A)
board.WriteI2C(PMIC,0x13,0x71)
board.WriteI2C(PMIC,0x14,0x42)
board.WriteI2C(PMIC,0x15,0x32)
board.WriteI2C(PMIC,0x16,0x52)
board.WriteI2C(PMIC,0x17,0x23)
board.WriteI2C(PMIC,0x03,0x1F)  # Enable Buck3 and LDO
board.WriteI2C(PMIC,0x0E,0x0A)  # Reprogram Buck2 power sequence
board.WriteI2C(PMIC,0x11,0x02)  # Configure nRSTOUT as global PGOOD
board.WriteI2C(PMIC,0x29,0xAE)  # Write new configuration CRC
board.WriteI2C(PMIC,0x04,0x1E)  # Enable configuration CRC
board.WriteI2C(PMIC,0x4A,0x2D)  # Write registers to EEPROM

time.sleep(1)
print "PMIC Reprogrammed"

图 3-6 和图 3-5 演示了 Analog LaunchPad 软件的脚本执行情况。

图 3-4 Analog LaunchPad SerDes 链路

图 3-5 Analog LaunchPad“Scripting”窗口

图 3-6 和图 3-7 展示了重新编程前后的 PMIC 电源序列。

图 3-6 TPS65033000 默认电源序列

图 3-7 TPS65033000 在重新编程后的电源序列