DDC_SDA_DRIVE_TGUI
#define DDC_MASK_TGUI (DDC_SCL_DRIVE_TGUI | DDC_SDA_DRIVE_TGUI)
reg &= ~DDC_SDA_DRIVE_TGUI; /* disable drive - don't drive hi */
reg |= DDC_SDA_DRIVE_TGUI; /* drive low */