Posted on November 15, 2017 at 11:38 Hi
We are using Tianma’s - TM070RVHG01 (800X480 resolution) TFT in our design with STM32F429 processor working at 168 MHz frequency. We are using EmWin Library on RTX operating system with LTDC support. We are statically storing the required ARGB8888 format in external SDRAM. The data is loaded from SDRAM to LTDC (STM32F4 LCD Controller) using DMA2D /FMC interface (Flexible Memory Controller – Working at 168/2 MHz).
The colour configuration is ARGB8888 and driver configuration of EmWin is GUI_LIN_32.
From datasheet (attached for reference) we understand that minimum DCLK is 28 MHz. So we are setting the DCLK as 28 MHz and calculated the parameters for LTDC which are as follows.
From Datasheet
HSYNC Width
20
VSYNC Width
3
HBP
46
VBP
23
Active Width
800
Active Height
480
BVBP
23
HFP
210
VFP
22
Calculated Value for LTDC Register
HSW
19
VSH
2
AHBP
65
AVBP
25
AAW
865
AAH
505
TOTAL W
1075
TOTAL H
527
Issue :
- We are find Tearing Effect in the display and the same time if we probe we could find FIFO underrun issue. Please let us know the above setting as correct for 28 MHz DCLK.
- When we reduce the DCLK to 24 MHz the display is stable but we are facing flicker issue.
Queries :
Is there any solution for the above problems without using multi buffer support. Also could you send sample source running on any RTOS for reference ?
