Samsung S3C2440A - Manual (Page 371)

S3C2440A RISC MICROPROCESSOR LCD CONTROLLER
15-3
BLOCK DIAGRAM
System Bus
LPC3600 is a timing control logic unit for LTS350Q1-PD1 or LTS350Q1-PD2.
LCC3600 is a timing control logic unit for LTS350Q1-PE1 or LTS350Q1-PE2.
REGBANK
LCDCDMA
VIDPRCS
LPC3600
TIMEGEN
VD[23:0]
VCLK /LCD_HCLK
VLINE / HSYNC / CPV
VFRAME / VSYNC / STV
VM / VDEN / TP
LCD_LPCOE / LCD_LCCINV
LCD_LPCREV / LCD_LCCREV
LCD_LPCREVB / LCD_LCCREVB
.
.
.
VIDEO
MUX
LCC3600
Figure 15-1. LCD Controller Block Diagram
The S3C2440A LCD controller is used to transfer the video data and to generate the necessary control signals,
such as VFRAME, VLINE, VCLK, VM, and so on. In addition to the control signals, the S3C2440A has the data
ports for video data, which are VD[23:0] as shown in Figure 15-1. The LCD controller consists of a REGBANK,
LCDCDMA, VIDPRCS, TIMEGEN, and LPC3600 (See the Figure 15-1 LCD Controller Block Diagram). The
REGBANK has 17 programmable register sets and 256x16 palette memory which are used to configure the LCD
controller. The LCDCDMA is a dedicated DMA, which can transfer the video data in frame memory to LCD driver
automatically. By using this special DMA, the video data can be displayed on the screen without CPU intervention.
The VIDPRCS receives the video data from the LCDCDMA and sends the video data through the VD[23:0] data
ports to the LCD driver after changing them into a suitable data format, for example 4/8-bit single scan or 4-bit dual
scan display mode. The TIMEGEN consists of programmable logic to support the variable requirements of
interface timing and rates commonly found in different LCD drivers. The TIMEGEN block generates VFRAME,
VLINE, VCLK, VM, and so on.
The description of data flow is as follows:
FIFO memory is present in the LCDCDMA. When FIFO is empty or partially empty, the LCDCDMA requests data
fetching from the frame memory based on the burst memory transfer mode (consecutive memory fetching of 4
words (16 bytes) per one burst request without allowing the bus mastership to another bus master during the bus
transfer). When the transfer request is accepted by bus arbitrator in the memory controller, there will be four
successive word data transfers from system memory to internal FIFO. The total size of FIFO is 28 words, which
consists of 12 words FIFOL and 16 words FIFOH, respectively. The S3C2440A has two FIFOs to support the dual
scan display mode. In case of single scan mode, one of the FIFOs (FIFOH) can only be used.