SainSmart DDS120/Info
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lsusb (vendor firmware from I²C EEPROM, not uploaded from PC, PCB jumper fitted)
$ lsusb -v -d 8102:8102
Bus 006 Device 052: ID 8102:8102
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x8102
idProduct 0x8102
bcdDevice 0.00
iManufacturer 1 BUUDAI
iProduct 2 USB102
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 46
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xc0
Self Powered
MaxPower 500mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 4
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 0
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0400 1x 1024 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x04 EP 4 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x86 EP 6 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x88 EP 8 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Device Qualifier (for other device speed):
bLength 10
bDescriptorType 6
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
bNumConfigurations 1
Device Status: 0x0000
(Bus Powered)
lsusb (before firmware upload, PCB jumper removed)
$ lsusb -v
Bus 001 Device 026: ID 04b4:8613 Cypress Semiconductor Corp. CY7C68013 EZ-USB FX2 USB 2.0 Development Kit
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 255 Vendor Specific Class
bDeviceSubClass 255 Vendor Specific Subclass
bDeviceProtocol 255 Vendor Specific Protocol
bMaxPacketSize0 64
idVendor 0x04b4 Cypress Semiconductor Corp.
idProduct 0x8613 CY7C68013 EZ-USB FX2 USB 2.0 Development Kit
bcdDevice a0.01
iManufacturer 0
iProduct 0
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 171
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 0
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 1
bNumEndpoints 6
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x01 EP 1 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x04 EP 4 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x86 EP 6 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x88 EP 8 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 2
bNumEndpoints 6
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x01 EP 1 OUT
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x04 EP 4 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x86 EP 6 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x88 EP 8 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 3
bNumEndpoints 6
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x01 EP 1 OUT
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x04 EP 4 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x86 EP 6 IN
bmAttributes 1
Transfer Type Isochronous
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x88 EP 8 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Device Qualifier (for other device speed):
bLength 10
bDescriptorType 6
bcdUSB 2.00
bDeviceClass 255 Vendor Specific Class
bDeviceSubClass 255 Vendor Specific Subclass
bDeviceProtocol 255 Vendor Specific Protocol
bMaxPacketSize0 64
bNumConfigurations 1
Device Status: 0x0000
(Bus Powered)
Vendor firmware
We use an open-source firmware that is part of sigrok-firmware-fx2lafw for this device (i.e., not the vendor firmware). The section below contains some historic information about the vendor firmware for those interested, though.
The vendor firmware is contained on the I²C EEPROM. The FX2 boots directly into that firmware. It uses the following 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. |
Open-source firmware details
The vendor firmware is contained on the I²C EEPROM. The FX2 boots directly into that firmware. However, we replace it (only in RAM, the EEPROM is never modified) with an open-source firmware that is part of sigrok-firmware-fx2lafw when the device is attached to USB.
The open source firmware is currently missing the following planned features:
- <1MHz, 2, 3, 5, 6, 7.5, 9.6, 10, 15, 24, 30 MHz sampling rate support
- Turn on/off the calibration pulse
- Change frequency of the calibration pulse (add 10kHz, 100kHz and 1MHz)
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. The following does not correlate with measure on real hardware, there is a 6th gain position that is working though. It is very similar to another gain and was most likely omitted because of that.
# Channel 0: PC1=1; PC2=0; PC3= 0 -> Gain x0.1 = -20dB -> 0x02 (1V) PC1=1; PC2=0; PC3= 1 -> Gain x0.2 = -14dB -> 0x0A (0.5V) PC1=1; PC2=1; PC3= 0 -> Gain x0.4 = -8dB -> 0x06 (0.250V) PC1=0; PC2=0; PC3= 0 -> Gain x0.5 = -6dB -> 0x00 (0.200V) PC1=0; PC2=0; PC3= 1 -> Gain x1 = 0dB -> 0x08 (0.100V) PC1=0; PC2=1; PC3= 0 -> Gain x2 = +6dB -> 0x04 (0.050V) # Channel 1: PE1=1; PC4=0; PC5= 0 -> Gain x0.1 = -20dB -> 0x02 (1V) PE1=1; PC4=0; PC5= 1 -> Gain x0.2 = -14dB -> 0x22 (0.5V) PE1=1; PC4=1; PC5= 0 -> Gain x0.4 = -8dB -> 0x12 (0.250V) PE1=0; PC4=0; PC5= 0 -> Gain x0.5 = -6dB -> 0x00 (0.200V) PE1=0; PC4=0; PC5= 1 -> Gain x1 = 0dB -> 0x20 (0.100V) PE1=0; PC4=1; PC5= 0 -> Gain x2 = +6dB -> 0x10 (0.050V)
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 controls the frequency of the calibration output on the PCB. It is driven by an ISR timer from the 8051 core of the FX2 chip.