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
Device, bottom
USB / LA connector
Analog connectors
LA probe cable
Probe cable details
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 |
Stopping a sampling run
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 | 0xff88 |
| 200 kHz | ... | |
| 150 kHz | ... | |
| 100 kHz | ... | |
| 90 kHz | ... | |
| 80 kHz | ... | |
| 70 kHz | ... | |
| 60 kHz | ... | |
| 50 kHz | ... | |
| 40 kHz | ... | |
| 30 kHz | ... | |
| 25 kHz | ... | |
| 20 kHz | ... | |
| 10 kHz | ... | |
| 9 kHz | ... | |
| 8 kHz | ... | |
| 7 kHz | ... | |
| 6 kHz | ... | |
| 5 kHz | ... | |
| 4 kHz | ... | |
| 3 kHz | ... | |
| 2.5 kHz | ... | |
| 2 kHz | ... | |
| 1 kHz | ... |