Difference between revisions of "SainSmart DDS120"
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(Add more Sainsmart DDS120 documentation) |
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|Trigger oscilloscope ||0x33 ||Possible values: 0x00 == start sampling. | |Trigger oscilloscope ||0x33 ||Possible values: 0x00 == start sampling. | ||
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== Resources == | == Resources == | ||
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[[Category:Device]] | [[Category:Device]] | ||
[[Category:Oscilloscope]] | [[Category:Oscilloscope]] | ||
== Gain stage == | |||
The gain stage is 2 stage approach. -6dB and -20dB on the first stage (attentuator). The second stage is then doing the gain by 3 different resistor values switched into the feedback loop. | |||
#Channel 0: | |||
PC1=1; PC2=0; PC3= 0 -> Gain x0.1 = -20dB | |||
PC1=1; PC2=0; PC3= 1 -> Gain x0.2 = -14dB | |||
PC1=1; PC2=1; PC3= 0 -> Gain x0.4 = -8dB | |||
PC1=0; PC2=0; PC3= 0 -> Gain x0.5 = -6dB | |||
PC1=0; PC2=0; PC3= 1 -> Gain x1 = 0dB | |||
PC1=0; PC2=1; PC3= 0 -> Gain x2 = +6dB | |||
#Channel 1: | |||
PE1=1; PC4=0; PC5= 0 -> Gain x0.1 = -20dB | |||
PE1=1; PC4=0; PC5= 1 -> Gain x0.2 = -14dB | |||
PE1=1; PC4=1; PC5= 0 -> Gain x0.4 = -8dB | |||
PE1=0; PC4=0; PC5= 0 -> Gain x0.5 = -6dB | |||
PE1=0; PC4=0; PC5= 1 -> Gain x1 = 0dB | |||
PE1=0; PC4=1; PC5= 0 -> Gain x2 = +6dB | |||
== AC/DC coupling == | |||
The coupling is controlled via 2 PhotoMOS chips. | |||
#Channel 0: | |||
PE3=0 Disable AC-coupling capacitor (DC-Coupling) | |||
PE3=1 Enable AC-coupling capacitor | |||
#Channel 1: | |||
PE0=0 Disable AC-coupling capacitor (DC-Coupling) | |||
PE0=1 Enable AC-coupling capacitor | |||
== 1kHz Calibration square wave == | |||
Pin PE2 controlls the level of the calibration output on the pcb. This is most likely driven by an ISR timer from the 8051 core of the FX2 chip. | |||
Revision as of 11:32, 16 March 2016
The SainSmart DDS120 is a USB-based, 2-channel oscilloscope with an analog bandwidth of 20MS/s and 48MS/s sampling rate.
See SainSmart DDS120/Info for more details (such as lsusb -v output) about the device.
- USB: Cypress CY7C68013A-100AXC (FX2LP) (datasheet)
- 256-byte I²C EEPROM: Microchip 24LC641 (datasheet)
- Crystal: 24MHz
- AD: AD8065ART-R2: (datasheet)
or in newer hardware
- AD: MXT2088 (datasheet)
- Opamp: Analog devices AD8065 (OPAMP)
- MUX: Texas Instruments CD4052B (2 x 1:4 MUX)
Photos
Device, top
Vendor Protocol
| Oscilloscope command | bRequest value | Notes |
|---|---|---|
| Set CH0 coupling | 0x24 | Possible values: 0x00, 0x08 (AC-coupling, DC-coupling). |
| Set CH1 coupling | 0x25 | Possible values: 0x20, 0x10 (AC-coupling, DC-coupling). |
| Set CH0 voltage range | 0x22 | Possible values: 0x08, 0x04, 0x00, 0x06, 0x02 (50mV, 100mV, 200mV, 500mV, 1-5V). |
| Set CH1 voltage range | 0x23 | Possible values: 0x20, 0x10, 0x00, 0x12, 0x02 (50mV, 100mV, 200mV, 500mV, 1-5V). |
| Set sampling rate | 0x94 | Possible values: 0x11, 0x01, 0x10 (240kHz, 2.4MHz, 48MHz). |
| Trigger oscilloscope | 0x33 | Possible values: 0x00 == start sampling. |
Resources
Gain stage
The gain stage is 2 stage approach. -6dB and -20dB on the first stage (attentuator). The second stage is then doing the gain by 3 different resistor values switched into the feedback loop.
#Channel 0: PC1=1; PC2=0; PC3= 0 -> Gain x0.1 = -20dB PC1=1; PC2=0; PC3= 1 -> Gain x0.2 = -14dB PC1=1; PC2=1; PC3= 0 -> Gain x0.4 = -8dB PC1=0; PC2=0; PC3= 0 -> Gain x0.5 = -6dB PC1=0; PC2=0; PC3= 1 -> Gain x1 = 0dB PC1=0; PC2=1; PC3= 0 -> Gain x2 = +6dB
#Channel 1: PE1=1; PC4=0; PC5= 0 -> Gain x0.1 = -20dB PE1=1; PC4=0; PC5= 1 -> Gain x0.2 = -14dB PE1=1; PC4=1; PC5= 0 -> Gain x0.4 = -8dB PE1=0; PC4=0; PC5= 0 -> Gain x0.5 = -6dB PE1=0; PC4=0; PC5= 1 -> Gain x1 = 0dB PE1=0; PC4=1; PC5= 0 -> Gain x2 = +6dB
AC/DC coupling
The coupling is controlled via 2 PhotoMOS chips.
#Channel 0: PE3=0 Disable AC-coupling capacitor (DC-Coupling) PE3=1 Enable AC-coupling capacitor
#Channel 1: PE0=0 Disable AC-coupling capacitor (DC-Coupling) PE0=1 Enable AC-coupling capacitor
1kHz Calibration square wave
Pin PE2 controlls the level of the calibration output on the pcb. This is most likely driven by an ISR timer from the 8051 core of the FX2 chip.