MT9M114_16 Datasheet, PDF (44/62 Pages) ON Semiconductor – High-Definition (HD) System-On- A-Chip (SOC) Digital Image Sensor

MT9M114: 1/6-Inch 720p High-Definition (HD) System-On-A-Chip (SOC) Dig-
ital Image Sensor
sync_enable=1, master=1 and position = N – 1 (where there are N devices in the daisy-
chain). The effect of enabling TMS as an output is to drive the TMS output low.
• MT9M114(2): This MT9M114 now has SADDR=0 and so will respond to slave address
ID0. The host configures this in the same way as MT9M114(1) with the exceptions
that it assigns ID-MT9M114(2), sets master=0 and position = N-2 (where there are N
devices in the daisy-chain). As before, the effect of enabling CHAIN as an output is to
drive the CHAIN output low.
• MT9M114(3): As for MT9M114(2): assign ID-MT9M114(3), master=0, position = N-3
• MT9M114(4): As for MT9M114(2): assign ID-MT9M114(4), master=0, position = N-4
Theory Of Operation
When multiple MT9M114 devices have been connected and configured as described
above, the multi-sync function operates as follows:
When the master device is placed in streaming mode (as the result of a mode change
initiated by the host) it generates an event on its CHAIN output. It then delays its own
streaming until the last of the slave devices has received an event signal.
When a slave device is placed in streaming mode (as the result of a mode change initi-
ated by the host) it delays streaming until it has received an event on its SADDR input.
Each slave in the daisy-chain propagates events received on its input. Each slave uses its
local value of “position” to delay its respond to an event. This allows an event propagated
down the daisy-chain to be acted upon simultaneously by all devices in the daisy-chain.
Using Multi-Sync
The host can use the normal mechanism to configure the MT9M114 and set them
streaming. It can do this in any order provided that it sets the master streaming last.
It is desirable (but not essential) for the master to be taken out of streaming mode first
(by using a host command).
At the time that the MT9M114 are placed in streaming mode, all MT9M114 must have
the same integration time The recommended mechanism is:
1) Boot each device into standby by enabling 'host-config' mode.
2) Reconfigure each device.
3) Wake each device and commence streaming using the Leave Standby command.
The MT9M114 need not maintain the same integration time once they are streaming.
All the MT9M114 must be operated with the same configuration (image size, output
format, PLL bypassed and frame timing). Any time that the configuration is to be
changed, all MT9M114 must be taken out of streaming mode (using host command),
reconfigured, then placed back in streaming mode (master last). This will allow the
output data to remain in synchronisation.
Clocking
The multi-sync mechanism requires that all MT9M114 devices in the daisy-chain are
operated synchronously on the same input clock. This constraint is imposed in order to
allow the event codes to be propagated synchronously from the master through to each
slave.
MT9M114/D Rev. 11, 2/16 EN
44
©Semiconductor Components Industries, LLC,2016.