PoLabs PoScope Basic2

PoLabs PoScope Basic2

The PoLabs PoScope Basic2 is a 16-channel, 8MHz, USB-based logic analyzer (plus oscilloscope, signal/pattern generator, and more).

See PoLabs PoScope Basic2/Info for some more details (such as lsusb -vvv output) on the device.

Components

• Silicon Labs C8051F32x: 8051-based microcontroller with USB and 10bit ADC (datasheet)
• Omron G3VM-401G: Analog switching MOS FET relay (datasheet)
• Analog Devices AD8544: CMOS RRIO quad general-purpose opamp (datasheet)
• Texas Instruments HC74 87K G4 A6EK (TODO)

Photos

• 

  Device, top

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  Device, bottom

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  USB / LA connector

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  Analog connectors

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  LA probe cable

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  Probe cable details

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  PCB, front

• 

  PCB, back

• 

  SiLabs F321

• 

  Analog Devices AD8544

• 

  Omron G3VM-401G

• 

  TI HC74

Protocol

Starting a sampling run

The command for starting an acquisition is a USB control transfer (request type: vendor-specific, request: 0x07, value: 0xffa0, index: 0x0000, length: 9).

The 9 bytes of data:

Byte	Description	Comments
0	Samplerate divider	(see table below)
1
2
3
4
5	Trigger mask	Bit 0 is the mask for probe 0, bit 7 is the mask for probe 7. The same byte is used as trigger mask byte for bus A or bus B (only one at a time is possible).
6
7
8

Sample rates

8MHz - 4MHz: Buffer size is 128 bytes, only bus A is available, ... Samplerate Divider Request value 8 MHz 0x00 0xfffd 6 MHz 0x01 0xfffc 4 MHz 0x02 0xfffa 2.6MHz - 2MHz: Buffer size is 1160 bytes, only bus A is available, ... Samplerate Divider Request value 2.6 MHz 0x03 0xfff7 2 MHz 0x04 0xfff4 1MHz - 600kHz: Buffer size is 1544 bytes, ... Samplerate Divider Request value 1 MHz 0x05 0xffe8 900 kHz 0x05 0xffe6 800 kHz 0x05 0xffe2 700 kHz 0x05 0xffde 600 kHz 0x05 0xffd8

500kHz and lower: Buffer size is only limited by the PC memory, ... Samplerate Divider Request value 500 kHz 0x05 0xffd0 400 kHz 0x05 0xffc4 300 kHz 0x05 0xffb0 250 kHz 0x06 0xffa0 200 kHz 0x06 0xff88 150 kHz 0x06 0xff60 100 kHz 0x06 0xff10 90 kHz 0x06 0xfef6 80 kHz 0x06 0xfed4 70 kHz 0x06 0xfeaa 60 kHz 0x06 0xfe70 50 kHz 0x06 0xfe20 40 kHz 0x06 0xfda8 30 kHz 0x06 0xfce0 25 kHz 0x06 0xfc40 20 kHz 0x06 0xfb50 10 kHz 0x06 0xf6a0 9 kHz 0x06 0xf596 8 kHz 0x06 0xf448 7 kHz 0x06 0xf29c 6 kHz 0x06 0xf060 5 kHz 0x06 0xed40 4 kHz 0x06 0xe890 3 kHz 0x06 0xe0c0 2.5 kHz 0x06 0xda80 2 kHz 0x06 0xd120 1 kHz 0x06 0xa240

Sample format

• 8-bit sampling: One sample is one byte. Bit 0 is the value of probe A.7 (or B.7), bit 7 is the value of probe A.0 (or B.0).
• 16-bit sampling: One sample consists of two bytes. Byte 0 corresponds to bus A, byte 1 corresponds to bus B. The bit assignment is the same as above.

Get current firmware version

There is a command to request the current firmware version (and date) from the device. The device returns 5 bytes as response:

Byte	Description	Comments
0	Major firmware version	Example: 0x03 means major version 3 (example version: 3.5).
1	Minor firmware version	Example: 0x05 means minor version 5 (example version: 3.5).
2	Firmware date (day)	Example: 0x1c means 28 (example date: 28/12/07).
3	Firmware date (month)	Example: 0x0c means 12 (example date: 28/12/07).
4	Firmware date (year, two digits)	Example: 0x07 means 2007 (example date: 28/12/07).

So in the example of 0x03 0x05 0x1c 0x0c 0x07 the resulting firmware version/date is 3.5 (28/12/07).