SNLS708 February 2023 DS90UB638-Q1
PRODUCTION DATA
In External FrameSync mode, an external signal is input to the DS90UB638-Q1 through one of the GPIO pins on the device. The external FrameSync signal may be propagated to one or more of the attached FPD-Link III Serializers through a GPIO signal in the back channel. The expected skew timing for external FrameSync mode is on the order of one back channel frame period or 3 µs when operating at 10 Mbps.
Enabling the external FrameSync mode is done by setting the FS_MODE control in the FS_CTL register to a value between 0x8 (GPIO0 pin) to 0xF (GPIO7 pin). Set FS_GEN_ENABLE to 0 for this mode.
To send the FrameSync signal on a port’s BC_GPIOx signal, the BC_GPIO_CTL0 or BC_GPIO_CTL1 register should be programmed for that port to select the FrameSync signal.