[U-Boot] omap: overo: Disable pull-ups on camera PCLK, HS and VS signals
The level shifters used on the Caspa camera module have a 4k output impedance. Combined with the 100uA pull-up resistors in the OMAP3, this raises the ground level to 400mV. Adding crosstalk between the pixel clock and the HS/VS signals on the flat cable (a ground line in between would have been nice), logic 0 levels can raise up to 650mV. This exceeds the camera input pins VIL maximum voltage. This change suggested-by Laurent Pinchart
Signed-off-by: Steve Sakoman steve@sakoman.com ---
diff --git a/board/overo/overo.h b/board/overo/overo.h index 42ef1b1..915f15b 100644 --- a/board/overo/overo.h +++ b/board/overo/overo.h @@ -160,10 +160,10 @@ const omap3_sysinfo sysinfo = { MUX_VAL(CP(DSS_DATA22), (IDIS | PTD | DIS | M0)) /*DSS_DATA22*/\ MUX_VAL(CP(DSS_DATA23), (IDIS | PTD | DIS | M0)) /*DSS_DATA23*/\ /*CAMERA*/\ - MUX_VAL(CP(CAM_HS), (IEN | PTU | EN | M0)) /*CAM_HS */\ - MUX_VAL(CP(CAM_VS), (IEN | PTU | EN | M0)) /*CAM_VS */\ + MUX_VAL(CP(CAM_HS), (IEN | PTU | DIS | M0)) /*CAM_HS */\ + MUX_VAL(CP(CAM_VS), (IEN | PTU | DIS | M0)) /*CAM_VS */\ MUX_VAL(CP(CAM_XCLKA), (IDIS | PTD | DIS | M0)) /*CAM_XCLKA*/\ - MUX_VAL(CP(CAM_PCLK), (IEN | PTU | EN | M0)) /*CAM_PCLK*/\ + MUX_VAL(CP(CAM_PCLK), (IEN | PTU | DIS | M0)) /*CAM_PCLK*/\ MUX_VAL(CP(CAM_FLD), (IDIS | PTD | DIS | M4)) /*CAM_FLD*/\ MUX_VAL(CP(CAM_D0), (IEN | PTD | DIS | M0)) /*CAM_D0*/\ MUX_VAL(CP(CAM_D1), (IEN | PTD | DIS | M0)) /*CAM_D1*/\
Hi Steve,
Le 30/09/2011 21:08, Steve Sakoman a écrit :
The level shifters used on the Caspa camera module have a 4k output impedance. Combined with the 100uA pull-up resistors in the OMAP3, this raises the ground level to 400mV. Adding crosstalk between the pixel clock and the HS/VS signals on the flat cable (a ground line in between would have been nice), logic 0 levels can raise up to 650mV. This exceeds the camera input pins VIL maximum voltage. This change suggested-by Laurent Pinchart
Signed-off-by: Steve Sakomansteve@sakoman.com
diff --git a/board/overo/overo.h b/board/overo/overo.h index 42ef1b1..915f15b 100644 --- a/board/overo/overo.h +++ b/board/overo/overo.h @@ -160,10 +160,10 @@ const omap3_sysinfo sysinfo = { MUX_VAL(CP(DSS_DATA22), (IDIS | PTD | DIS | M0)) /*DSS_DATA22*/\ MUX_VAL(CP(DSS_DATA23), (IDIS | PTD | DIS | M0)) /*DSS_DATA23*/\ /*CAMERA*/\
- MUX_VAL(CP(CAM_HS), (IEN | PTU | EN | M0)) /*CAM_HS */\
- MUX_VAL(CP(CAM_VS), (IEN | PTU | EN | M0)) /*CAM_VS */\
- MUX_VAL(CP(CAM_HS), (IEN | PTU | DIS | M0)) /*CAM_HS */\
- MUX_VAL(CP(CAM_VS), (IEN | PTU | DIS | M0)) /*CAM_VS */\ MUX_VAL(CP(CAM_XCLKA), (IDIS | PTD | DIS | M0)) /*CAM_XCLKA*/\
- MUX_VAL(CP(CAM_PCLK), (IEN | PTU | EN | M0)) /*CAM_PCLK*/\
- MUX_VAL(CP(CAM_PCLK), (IEN | PTU | DIS | M0)) /*CAM_PCLK*/\ MUX_VAL(CP(CAM_FLD), (IDIS | PTD | DIS | M4)) /*CAM_FLD*/\ MUX_VAL(CP(CAM_D0), (IEN | PTD | DIS | M0)) /*CAM_D0*/\ MUX_VAL(CP(CAM_D1), (IEN | PTD | DIS | M0)) /*CAM_D1*/\
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Applied to u-boot-arm/master, thanks.
Amicalement,
participants (2)
-
Albert ARIBAUD -
Steve Sakoman