I'd like to find a datasheet for an audio ADC used in an inexpensive
USB audio capture "card" so as to better understand how to use it and
what it can do as a low-frequency oscilloscope. It came from Amazon,
sold under the name "DIGITNOW! USB Audio Capture". It seems to work
surprisingly well, working with no issues on a Raspberry Pi 4 using
the stock RaspiOS version of Audacity. It also works under the latest
(not stock) version of xoscope, which had to be recompiled to obtain
ALSA support. I'm inexperienced with both programs, so the behavior
is somewhat confusing but it does seem worth exploring further.

The seller's tech support carefully misunderstands every question.

It's a one-chip dongle, the single IC is marked
IS821S
SHO3AO9OAGC
1O2DNMO19

All the O characters look the same, so they could be mixed with zeros.
Repeated searches using Google and DuckDuckGo have turned up nothing,
does anybody recognize at least a manufacturer?

Thanks for reading!

bob prohaska

On 11/05/2021 16:37, bob prohaska wrote:
I'd like to find a datasheet for an audio ADC used in an inexpensive
USB audio capture "card" so as to better understand how to use it and
what it can do as a low-frequency oscilloscope. It came from Amazon,
sold under the name "DIGITNOW! USB Audio Capture". It seems to work
surprisingly well, working with no issues on a Raspberry Pi 4 using
the stock RaspiOS version of Audacity. It also works under the latest
(not stock) version of xoscope, which had to be recompiled to obtain
ALSA support. I'm inexperienced with both programs, so the behavior
is somewhat confusing but it does seem worth exploring further.


paste here the relevant output of the command

lspci -vv

--
Adrian C

Adrian Caspersz wrote:
On 11/05/2021 16:37, bob prohaska wrote:
I'd like to find a datasheet for an audio ADC used in an inexpensive
USB audio capture "card" so as to better understand how to use it and


paste here the relevant output of the command

lspci -vv

The device is USB 2.0 and is plugged into the USB 2.0 ports on the Pi, which
aren't accessed via PCI.

lsusb reports

Bus 002 Device 002: ID 152d:1561 JMicron Technology Corp. / JMicron USA Technology Corp. JMS561U two ports SATA 6Gb/s bridge
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 007: ID 2034:0105
Bus 001 Device 005: ID 413c:3010 Dell Computer Corp. Optical Wheel Mouse
Bus 001 Device 004: ID 413c:2002 Dell Computer Corp. SK-8125 Keyboard
Bus 001 Device 003: ID 413c:1002 Dell Computer Corp. Keyboard Hub
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

I tend to think it's probably
Bus 001 Device 007: ID 2034:0105
which was the last USB device plugged in.

lspci reports

00:00.0 PCI bridge: Broadcom Limited Device 2711 (rev 10) (prog-if 00 [Normal decode])
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR+ FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast TAbort- TAbort- MAbort- SERR- PERR- INTx-
Latency: 0, Cache Line Size: 64 bytes
Interrupt: pin A routed to IRQ 61
Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
I/O behind bridge: 00000000-00000fff
Memory behind bridge: c0000000-c00fffff
Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast TAbort- TAbort- MAbort- SERR- PERR-
BridgeCtl: Parity+ SERR+ NoISA- VGA- MAbort- Reset- FastB2B-
PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
Capabilities: [48] Power Management version 3
Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold-)
Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=1 PME-
Capabilities: [ac] Express (v2) Root Port (Slot-), MSI 00
DevCap: MaxPayload 512 bytes, PhantFunc 0
ExtTag- RBE+
DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
RlxdOrd+ ExtTag- PhantFunc- AuxPwr+ NoSnoop+
MaxPayload 128 bytes, MaxReadReq 512 bytes
DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr- TransPend-
LnkCap: Port #0, Speed 5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s 2us, L1 4us
ClockPM+ Surprise- LLActRep- BwNot+ ASPMOptComp+
LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk-
ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
LnkSta: Speed 5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt+
RootCtl: ErrCorrectable- ErrNon-Fatal- ErrFatal- PMEIntEna+ CRSVisible+
RootCap: CRSVisible+
RootSta: PME ReqID 0000, PMEStatus- PMEPending-
DevCap2: Completion Timeout: Range ABCD, TimeoutDis+, LTR+, OBFF Via WAKE# ARIFwd-
DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled ARIFwd-
LnkCtl2: Target Link Speed: 5GT/s, EnterCompliance- SpeedDis-
Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
Compliance De-emphasis: -6dB
LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete-, EqualizationPhase1-
EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
Capabilities: [100 v1] Advanced Error Reporting
UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr-
CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
AERCap: First Error Pointer: 00, GenCap- CGenEn- ChkCap- ChkEn-
Capabilities: [180 v1] Vendor Specific Information: ID=0000 Rev=0 Len=028 ?
Capabilities: [240 v1] L1 PM Substates
L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+ L1_PM_Substates+
PortCommonModeRestoreTime=8us PortTPowerOnTime=10us
L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1-
T_CommonMode=1us LTR1.2_Threshold=0ns
L1SubCtl2: T_PwrOn=10us
Kernel driver in use: pcieport

01:00.0 USB controller: VIA Technologies, Inc. VL805 USB 3.0 Host Controller (rev 01) (prog-if 30 [XHCI])
Subsystem: VIA Technologies, Inc. VL805 USB 3.0 Host Controller
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR+ FastB2B- DisINTx+
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast TAbort- TAbort- MAbort- SERR- PERR- INTx-
Latency: 0, Cache Line Size: 64 bytes
Interrupt: pin A routed to IRQ 62
Region 0: Memory at 600000000 (64-bit, non-prefetchable) [size=4K]
Capabilities: [80] Power Management version 3
Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0+,D1-,D2-,D3hot-,D3cold+)
Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
Capabilities: [90] MSI: Enable+ Count=1/4 Maskable- 64bit+
Address: 00000000fffffffc Data: 6540
Capabilities: [c4] Express (v2) Endpoint, MSI 00
DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s 64ns, L1 1us
ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset- SlotPowerLimit 0.000W
DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
MaxPayload 128 bytes, MaxReadReq 512 bytes
DevSta: CorrErr+ UncorrErr- FatalErr- UnsuppReq+ AuxPwr+ TransPend-
LnkCap: Port #0, Speed 5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s 2us, L1 16us
ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp-
LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+
ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
LnkSta: Speed 5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
DevCap2: Completion Timeout: Range B, TimeoutDis+, LTR-, OBFF Not Supported
DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled
LnkCtl2: Target Link Speed: 5GT/s, EnterCompliance- SpeedDis+
Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
Compliance De-emphasis: -6dB
LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete-, EqualizationPhase1-
EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
Capabilities: [100 v1] Advanced Error Reporting
UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr-
CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
AERCap: First Error Pointer: 00, GenCap- CGenEn- ChkCap- ChkEn-
Kernel driver in use: xhci_hcd

[sorry about the messed up line breaks]

If you can find it in there my hat's off to you!

Thanks, for writing,

bob prohaska

On 13/05/2021 02:57, bob prohaska wrote:
Adrian Caspersz wrote:
On 11/05/2021 16:37, bob prohaska wrote:
I'd like to find a datasheet for an audio ADC used in an inexpensive
USB audio capture "card" so as to better understand how to use it and


paste here the relevant output of the command

lspci -vv

The device is USB 2.0 and is plugged into the USB 2.0 ports on the Pi, which
aren't accessed via PCI.

lsusb reports

Bus 002 Device 002: ID 152d:1561 JMicron Technology Corp. / JMicron USA Technology Corp. JMS561U two ports SATA 6Gb/s bridge
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 007: ID 2034:0105
Bus 001 Device 005: ID 413c:3010 Dell Computer Corp. Optical Wheel Mouse
Bus 001 Device 004: ID 413c:2002 Dell Computer Corp. SK-8125 Keyboard
Bus 001 Device 003: ID 413c:1002 Dell Computer Corp. Keyboard Hub
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

I tend to think it's probably
Bus 001 Device 007: ID 2034:0105
which was the last USB device plugged in.


If you can find it in there my hat's off to you!


Yup, my bad lsusb it should have been.

https://the-sz.com/products/usbid/in...34&p=0x0105&n=

iSoft Silicon, Inc. (defunct website)

https://web.archive.org/web/20190122...oducts_01.html

"IS-821
USB stereo ADC, stereo line-in and mono MIC-in, I2C interface, 28-pin
SSOP pack"

Bit of a dead end, but that site says

"Softs audio chips are fully compatible the USB plug-and-play profile.
Under most OS platforms, there is no private driver required."

However for electrical specs, pinout etc, I've drawn a blank.

--
Adrian C

Adrian Caspersz wrote:

https://the-sz.com/products/usbid/in...34&p=0x0105&n=

iSoft Silicon, Inc. (defunct website)

https://web.archive.org/web/20190122...oducts_01.html

"IS-821
USB stereo ADC, stereo line-in and mono MIC-in, I2C interface, 28-pin
SSOP pack"

Bit of a dead end, but that site says

"Soft?s audio chips are fully compatible the USB plug-and-play profile.
Under most OS platforms, there is no private driver required."

However for electrical specs, pinout etc, I've drawn a blank.


Hmmm. The last reply from tech support was "... we don't quite understand what the question you are asking means".

Maybe it's absurd, but it makes me wonder if the device is a Trojan.
No....that's too clever....

Thanks for humoring me,

bob prohaska

[top post for brevity]

A keyword search for 2034:0105 led to
https://shkspr.mobi/blog/2020/08/ins...record-player/
which led to
https://www.ti.com/lit/ds/symlink/pcm2900.pdf
an obsolete USB audio chip.

Trouble is, that chip employs a crystal and the device I'm
dealing with has no crystal. If it's an unlicensed clone it
got improved. Perhaps just a hijacked device ID?

Anyway, it was a fun goose chase.

Thanks for reading,

bob prohaska

bob prohaska wrote:
Adrian Caspersz wrote:

https://the-sz.com/products/usbid/in...34&p=0x0105&n=

iSoft Silicon, Inc. (defunct website)

https://web.archive.org/web/20190122...oducts_01.html

"IS-821
USB stereo ADC, stereo line-in and mono MIC-in, I2C interface, 28-pin
SSOP pack"

Bit of a dead end, but that site says

"Soft?s audio chips are fully compatible the USB plug-and-play profile.
Under most OS platforms, there is no private driver required."

However for electrical specs, pinout etc, I've drawn a blank.


Hmmm. The last reply from tech support was "... we don't quite understand what the question you are asking means".

Maybe it's absurd, but it makes me wonder if the device is a Trojan.
No....that's too clever....

Thanks for humoring me,

bob prohaska