User's Manual

Table Of Contents
CAMERA INTERFACE S3C2450X RISC MICROPROCESSOR
23-12
4.5.1 Timing diagram for Last IRQ (Camera capture mode)
IRQ except LastIRQ is generated before image capturing. Last IRQ which means capture-end can be set by
following timing diagram. LastIRQEn is auto-cleared and ,as mentioned, SFR setting in ISR is for next frame
command. So, for adequate last IRQ, you should follow next sequence between LastIRQEn and
ImgCptEn/ImgCptEn_CoSc/ImgCptEnPrSC. It is recommended that ImgCptEn/ImgCptEn_CoSc/ImgCptEnPrSC
are set at same time and at last of SFR setting in ISR. FrameCnt which is read in ISR, means next frame count.
On following diagram, last captured frame count is “1”. That is, Frame 1 is the last-captured frame among frame
0~3. FrameCnt is increased by 1 at IRQ rising.
- Camera input capture path (applied both Preview & Codec path)
ISR
region
ISR
region
ISR
region
VSYNC
ISR
region
ImgCptEn(cmd)
LastIRQEn
Capture O Capture O Capture O Capture X
IRQ
Auto cleared
Last
IRQ
ISR
region
ISR
region
ISR
region
FrameCnt
Capture O Capture O
(Frame_3) (Frame_0) (Frame_1) (Frame_3) (Frame_0)
0 1 2 3 0 1
3
ISR
region
ISR
region
ISR
region
VSYNC
ISR
region
ImgCptEn(cmd)
LastIRQEn
Capture O Capture O Capture O Capture X
IRQ
Last IRQ
Low
ISR
region
ISR
region
ISR
region
FrameCnt
Capture O Capture O
(Frame_3) (Frame_0) (Frame_1) (Frame_2) (Frame_3)
0 1 2 2 3 0
3
VSYNC
IRQ
A
B
A = 8 cycle of pixel clock + 3 cycle of system clock
B = 1 cycle of system clock
4.5.2 Timing diagram for IRQ (Memory data processing mode)
MSDMA(Memory data input path) input is applied only preview path !!! when SFR SEL_DMA_CAM = ‘1’ ). Codec
path doesn’t care. codec path is applied a only camera capturing case. IRQ is generated after Preview DMA
operation done per frame. This mode is aware of starting point by user’s SFR setting (ENVID_MS ‘0’ ‘1’). so,
this mode doesn’t need IRQ of starting point and LastIRQ. FrameCnt is increased by 1 at ENVID_MS low to rising
(‘0’ ‘1’) and ImgCptEn_PrSC ‘1’