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MT9T111_DG - Rev. B 9/10 EN
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©2007 Aptina Imaging Corporation. All rights reserved.
MT9T111: Developer Guide
RX and TX FIFO Watermark
Preliminary
RX and TX FIFO Watermark
The MT9T111 has two internal FIFO blocks to support different clock domains. The RX
FIFO handles the data flow from the sensor to the IFP, and the TX FIFO handles the data
flow from the IFP to the output interface block, as shown in Figure 6.
The watermark indicates the level of the FIFO to start the read out operation for contin-
uous image data flow. Both FIFOs must be programmed with correct watermark data to
operate correctly, as shown in Table 11. The Register Wizard tool generates the proper
watermark values for both RX and TX FIFOs for different clock settings and output image
sizes. The MT9T111 programs the TX FIFO watermark automatically, but also allows the
user to program the watermark values manually. To activate the manual override, the
user must program the TX FIFO watermark and set the manual flag, as shown in
Table 11. The MT9T111 does not calculate the RX FIFO watermark, and always uses the
user programmed value.
Figure 6:
Watermark Block Diagram
Table 11:
Watermark Values to be Programmed
Map
Address
for 0x098E
Bits
Description
CAM1 Control
0x4846
[15:0]
Camera1 (internal sensor) context A RX FIFO watermark value.
CAM1 Control
0x4882
[15:0]
Camera1 (internal sensor) context B RX FIFO watermark value.
CAM2 Control
0x4C46
[15:0]
Camera2 (external sensor) context A RX FIFO watermark value.
Output Interface
Parallel
Interface
MIPI
Transmitter
TX
FIFO
Sensor
MT9T013
Sensor
Core
System Interface
PLL
Clock Dividers
Image Flow
Processor
Color
Pipeline
JPEG
MT 9 T 1 1 1
PIXCLK
MIPICLK
Sensor
CLK
SOC CLK
PIXCLK
TX FIFO
Watermark
RX FIFO
Watermark
RX
FIFO