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QHY42PRO Adanced Shutter Measurement
2019 年 12 月 11 日
The QHY42PRO support the advanced Trig Out signal. Support both QHYCCD 4PIN , 5PIN , 6PIN GPIO port defination. These defination can be switched with the REG39. And there is a TrigOut output pulse enable resigster REG142, This regsiter is used to disable the output signal to avoid some unexpected signal output, like during the camera initialize, and mode change.
To active the QHY42PRO advanced Trig Out function, you need to upgrade the two FPGA firmware in the camera with:
REG39[3:0] GPIO Mode Switch Register.
0:I2C controlled GPIO signal output
3: 4PIN
4: Multiple Camera Sync-Working mode . Master
5: Multiple Camera Sync-Working mode . Slave
6 to 15: Undefined
REG142 TrigEnable Control Resgister
0: Disable the Output pulse
1: Enable the Output pulse.
5PIN cable color define
Shutter Messurement
5PIN socket define (Face to the camera port side) and please note there is a red mark point.

Important Note:
The four IO in this port is the directly digital output , no opto-isolated. The IO standard is the 2.5V Level. High level is 2.5V. Low level is 0V. The 5pin is connected with the camera hardware with a ESD protec component. For the 5PIN I/O config, the four IO is directly output only. Please do not input any signal into it or connect it any voltage. Even it has ESD protect. But please take it carefully to avoid the static damage.
Don't use the original open-drain connect method for it !!! Any voltage applied in these IO exceed 2.5V may damge the camera!!!!!
ShuterMessure Waveform
The shutterMessure waveform is the high precise waveform to indicate the begin/end exposure. Please note for QHY42PRO, it is the begin/end exposure of the ROW 0. The rising edge is the exposure beginning and the falling edge is the exposure ending. The width is the exposure time. You can connect the GPS messurement device to messure it directly. This waveform output support both Live video mode, Single mode and Burst mode
For rolling shutter CMOS, you need to get to know the Line Period then you can calcuate other rows exposure time beginning and ending. With this formual:
The t(begin2) is the row 2 beginning time. So :
The same as the t(end2)
The LinePeriod is a fixed value for all QHY42PRO cameras. So you only need to test one time.And write down of it. Please note in different SPEED setting . The LinePeriod will be not the same. Only SPEED setting will effect it. You can messure each SPEED setting and write down of it.
TrigOut (High Speed)
TrigOut singal is for normal messurement, not for high precise messurement. The TrigOut signal is the vertical Sync signal in the camera. It is a short pulse (the pulse is low level) . The falling edge of the TrigOut is close to end exposure of row 0 and the rising edge is nothing. This waveform output support both Live video mode, Single mode and Burst mode.
About SMA Trig In, Trig Out Port.
There is two SMA port on the camera. Trig In and Trig Out. Trig In is to input a hardware signal to trig the camera begin a capture in hardware. Trig Out is output the TrigOut signal or Shutter Measure signal or other signal. These two port is opto-isolated port and it is low speed port (due to the slow rising/falling edge of opto-isolater). But it has better ESD protect for the camera and suitable for longer cable.
REG39 BIT[7:6] Mode Switch Bit for TrigIn Port
0: ShutterMeasure Waveform Output
1: TrigOut (Vertical Sync) Output
2: Undefined
3: Undefined
REG39 BIT[5:4] Mode Switch Bit for TrigOut Port
0: Undefined
1: Undefined
2: Undefined
3: Undefined
Since the structure of the opto-isolator , the TrigOut port need have a pull up resistor to pull it up to a voltage. For example, 5kohm to connect to the 3.3V-12V.
For TrigIn, you can input a voltage with a current limitation resistor in series with it.
Sample WaveForm
LinePeriod Waveform in 5PIN port

TrigOut waveform in 5PIN Port

Shutter Measure Waveform in 5PIN PORT @ exposure time set to 20.0ms

Shutter Measure Waveform in 5PIN PORT @ exposure time set to 1.0ms

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