MT9V111 Datasheet, PDF (38/46 Pages) Micron Technology – 1/4-Inch SOC VGA CMOS Active-Pixel Digital Image Sensor

MT9V111 - 1/4-Inch SOC VGA Digital Image Sensor
Two-wire Serial Interface Sample Write and Read Sequences
Two-wire Serial Interface Sample Write and Read Sequences
(with SADDR = 1)
16-Bit Write Sequence
A typical write sequence for writing 16 bits to a register is shown in Figure 16. A start bit
given by the master, followed by the write address, starts the sequence. The image sen-
sor will then give an acknowledge bit and expects the register address to come first, fol-
lowed by the 16-bit data. After each eight-bit the image sensor will give an acknowledge
bit. All 16 bits must be written before the register will be updated. After 16 bits are trans-
ferred, the register address is automatically incremented, so that the next 16 bits are
written to the next register. The master stops writing by sending a start or stop bit.
Figure 16: Timing Diagram Showing a Write to Reg0x09 with Value 0x0284
SCLK
SDATA
START
0xB8 ADDR
ACK
Reg0x09
ACK
0000 0010
ACK
1000 0100
STOP
ACK
16-Bit Read Sequence
A typical read sequence is shown in Figure . First the master has to write the register
address, as in a write sequence. Then a start bit and the read address specifies that a read
is about to happen from the register. The master then clocks out the register data eight
bits at a time. The master sends an acknowledge bit after each eight-bit transfer. The
register address is auto-incremented after every 16 bits is transferred. The data transfer
is stopped when the master sends a no-acknowledge bit.
Figure 17: Timing Diagram Showing a Read from Reg0x09; Returned Value 0x0284
SCLK
SDATA
START
0xB8 ADDR
ACK
Reg 0x09
ACK
0xB9 ADDR
ACK
0000 0010
ACK
1000 0100
STOP
NACK
09005aef80e90084
MT9V111_2.fm - Rev. G 1/05 EN
38
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