SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
Figure 12-466 depicts a simplified internal block diagram of the CSI_TX_IF and its surroundings.
The CSI2 core streams 4 channels of data to the several export paths.
Stream0 (from PSI_L) goes through the PSI_L that converts 128(4x32) bits pixel data and converts it to single 32-bit CSI streaming protocol of pixel data. Each 128 bit set of PSI_L data is split into N M-bit data transfers based on the SIZE_CFG bitfield setting in the CSI_TX_IF_DMACNTX_j register for a given thread. See memory organization details in CSI_TX_IF Data Memory Organization Details. Via register mapping in the CSI_TX_IF_DMACNTX_j register the PSI_L thread ID is mapped to a virtual channel and a data type. The CSI_TX_IF_DMACNTX_j register is the thread filter. There are 32 dma context registers. Figure 12-467 shows the stream to PSI_L thread mapping.
Software must take the following notes in consideration
Registers CSI_TX_IF_L2L_DELAY_j control the line start to next line start. Also register CSI_TX_IF_L2L_DELAY_j control the last line of frame to next start of frame first line start of next frame. Buffering of PSI_L data is 2k×128 RAM.
Stream0 (from CSI_RX_IF) is a loopback stream from the CSI receiver muxed with PSI_L data stream.
Stream1 streams data from the Color Bar generator. It supports YUV422 8bit format only. CSI_TX_IF_COLOR_PARAM register is used to control height and width information. Width is divided by 8 for each color section. Colors are defined below. Transfers are done on the Stream1 interface in 32-bit packed 8-bit pixel format(required programming in CSI_TX_IF core). Virtual channel and data type is configurable in CSI_TX_IF_COLOR_CNTL register. Data selection inside CSI_TX_IF controller maps data type information. CSI_TX_IF_COLOR_START_DELAY register can configure delays from enabled to start. CSI_TX_IF_COLOR_LINE_DELAY, and CSI_TX_IF_COLOR_FRAME_DELAY register can delay last line to first line of new frame. Once enabled, it will continuously send out frames until disabled. Once disabled, it will stop at end of current frame. Table 12-402 shows the Color Bar format.
Color | Y | CB | CR |
---|---|---|---|
White | 235 | 128 | 128 |
Yellow | 162 | 44 | 142 |
Cyan | 131 | 156 | 44 |
Green | 112 | 72 | 58 |
Magenta | 84 | 184 | 198 |
Red | 65 | 100 | 212 |
Blue | 35 | 212 | 114 |
Black | 16 | 128 | 128 |
It is a requirement that only PSI_L/DMA, color bar, or CSI_RX_IF loopback streams are not active at the same point in time. The intended use model is not to have multiple combinations active at any given time. The main issue with this is that RAMs are not sized for concurrent operation and will likely overflow resulting in data loss.