Datasheet

PDF: 09005aef8202ec2e/Source: 09005aef8202ebf7 Micron Technology, Inc., reserves the right to change products or specifications without notice.
MT9D111__7_REV5.fm - Rev. B 2/06 EN
148 ©2004 Micron Technology, Inc. All rights reserved.
MT9D111 - 1/3.2-Inch 2-Megapixel SOC Digital Image Sensor
Start-Up and Usage
Micron Confidential and Proprietary
Since the quantization memory stores 3 sets (luma and chroma) of quantization tables,
the one that is used for the current frame JPEG encoding is indicated in bit 7:6 of
jpeg.config (quantization table ID). Bit 5 of jpeg.config determines who is responsible
for setting the quantization table ID. If it is “0,” the host processor must program quanti-
zation table ID for every JPEG compressed frame (no need to reprogram it if subsequent
JPEG frames use the same quantization tables). If it is “1,” the JEPG driver sets quantiza-
tion table ID to “0” at the start of JPEG capture (be it still or video) and automatically
select next set of quantization tables for the subsequent frames when the current JPEG
frame is unsuccessful.
Bit 7:6 of jpeg.config = 0, 1, and 2 indicates first, second, and third set of quantization
tables, respectively.
Error Handling and Handshaking
When the capturing of a JPEG snapshot is unsuccessful, the JPEG driver can be config-
ured to enable encoding subsequent frames until it is successful by setting bit 2 of
jpeg.config to “1.” For capturing JPEG video, MT9D111 always encodes subsequent
frames no matter what value bit 2 of jpeg.config is set to.
If bit 1 of jpeg.config is “1,” handshaking with the host processor at every erroneous
JPEG frame is required. When JPEG status register indicates that there is an error in the
current JPEG frame, JPEG encoding is stopped until the host processor sets bit 3 of
jpeg.config to “1” to indicate it is ready to receive next JPEG frame. If the host processor
does not respond to an erroneous JPEG frame within jpeg.timeoutFrames frames, JPEG
capture is terminated. If bit 1 of jpeg.config is “0” or if there is no error in JPEG status
register, no handshaking is required.
The handshaking mechanism is provided so that the host processor has sufficient time
to handle the erroneous JPEG frame and react upon the error condition. For example, if
the JPEG status register indicates FIFO overflow, the host processor should increase
quantization value by changing quantization table scaling factor or selecting another set
of the preloaded quantization tables. If spoof oversize error occurs, the host processor
should increase the spoof frame size by programming registers R16 and R17 on IFP Reg-
ister Page 2 and/or increase quantization value.
Start-Up and Usage
The start-up sequence consists of the following:
1. Power-up
2. Hardware reset
3. Configure and enable PLL
4. Configure pad slew rate
5. Configure preview mode
6. Configure and enable auto focus
7. Configure capture mode
8. Perform lock or capture
To start the part, power up power supplies, provide an input clock, and perform a hard-
ware reset.