4d Systems uCAM-II Datenbogen
4D SYSTEMS µCAM-II
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7. Command Protocol
This section outlines command usage and protocol transaction between the host and the uCAM-II module.
ACK and NAK responses are typical as replies from the Camera after sending a command, however silence is
also possible if the camera has gone to sleep. Please refer to Section 6.9 and 6.10 for ACK/NAK information.
ACK and NAK responses are typical as replies from the Camera after sending a command, however silence is
also possible if the camera has gone to sleep. Please refer to Section 6.9 and 6.10 for ACK/NAK information.
7.1. Synchronising the uCAM-II
Send the SYNC command until receiving the ACK command from uCAM-II (usually an ACK command is received
after sending the SYNC command 25 times). This must be performed following a power-up.
after sending the SYNC command 25 times). This must be performed following a power-up.
Note 1:
The host should send the SYNC command one by one continuously until receiving the ACK and SYNC
commands back from the uCAM-II module. Sometimes up to 25 to 60 SYNC commands maybe required before
the module will respond. It is suggested that you start with a 5ms pause between retries and increase by 1ms
for each additional retry. After receiving the response, the host should reply with the ACK command to finalise
the synchronisation process.
Note 2:
After synchronising and establishing a communications link with the uCAM-II, allow up to 1-2 seconds before
capturing the first image. The uCAM-II needs this time to allow its AGC and AEC circuits to stabilise, otherwise
the received image luminance maybe too high or too low.
Note 3:
The SYNC command is used to wake the camera up from Sleep (see Section 5.5), and is also used to keep the
camera awake by periodically sending this command. Periodically sending commands is only required if no
commands have been sent. If communications are occurring between the Host and the Camera, the camera
will stay awake. When they stop for 15 seconds, the camera will go to sleep and will require waking with the
SYNC command.
The host should send the SYNC command one by one continuously until receiving the ACK and SYNC
commands back from the uCAM-II module. Sometimes up to 25 to 60 SYNC commands maybe required before
the module will respond. It is suggested that you start with a 5ms pause between retries and increase by 1ms
for each additional retry. After receiving the response, the host should reply with the ACK command to finalise
the synchronisation process.
Note 2:
After synchronising and establishing a communications link with the uCAM-II, allow up to 1-2 seconds before
capturing the first image. The uCAM-II needs this time to allow its AGC and AEC circuits to stabilise, otherwise
the received image luminance maybe too high or too low.
Note 3:
The SYNC command is used to wake the camera up from Sleep (see Section 5.5), and is also used to keep the
camera awake by periodically sending this command. Periodically sending commands is only required if no
commands have been sent. If communications are occurring between the Host and the Camera, the camera
will stay awake. When they stop for 15 seconds, the camera will go to sleep and will require waking with the
SYNC command.
SYNC
(AA 0D 00 00 00 00)
SYNC
(AA 0D 00 00 00 00)
SYNC
(AA 0D 00 00 00 00)
ACK
(AA 0E 0D xx 00 00)
SYNC
(AA 0D 00 00 00 00)
Max. 60 times
ACK
(AA 0E 0D xx 00 00)
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