FAQ's S Last changes: 07.05.2007 - Glyn High-Tech Distribution

FAQ’s
Q: I use a Headset test board with UAC3556. Sound is very noisy, clacking and
chattering. I thought, that the problem was with bad ground connection by wires. I
assembled it - but the sound is the same bad.
A: If you use the internal ROM firmware or a "Codec" fw from the SDK, the noise is
caused by the mismatch of SW and HW configuration. UAC3556B has Codec fw in the
internal ROM. Codec fw need a "out of band noise filter", see datasheet
differences in the Codec and headset schematics page 49 and 50 Pins 50 - 55. So
you have to use a headset type -> UAC3554B. For development you can use a big
EEPROM and load a headset fw from the SDK to the EEPROM. The 3556 has a big
internal RAM to download complete fw from a EEPROM. So please download the SDK and
look in the "UACB Eeprom Configuration.pdf" for Register 0x09.
Q: if I want to use our own VID/PID, where can I change this in the firmware
A: use the file data_sec1.asm from the SDK and search for
.rword 0x074d ; idVendor 0x074d is Micronas ID
.rword 0x3556 ; idProduct UACB 3556
there you change VID/PID.
Q: can I change the VID/PID direct in the *.hex file without recompile my assembler
files
A: Yes, please read document "UACB Eeprom Configuration.pdf". On page 7 is the
position described.
Q: I use a 2k EEPROM only. Therefore I can only use configuration section (section1).
But when I compile a firmware the *.hex file is to large for my EEPROM.
A: By default the compiler generates a configuration Section (section1) and also a
firmware section (section2). You have to comment out the firmware section. Go to
emu_flash.asm and search for:
;; include section 3 data here (V8 program code)
EMU_S3_DATA:
.include "results/emu_rom.asm"; generated by a perl script
EMU_S3_DATA_END:
and change to
;; include section 3 data here (V8 program code)
EMU_S3_DATA:
;.include "results/emu_rom.asm"; generated by a perl script
EMU_S3_DATA_END:
no section 3 (firmware section) will be build.
Q: I want save power and do not need all features of UACB is this possible
A: Yes, please refer reducing_power_by_using_the_reduced_featureset.pdf in the
Service Area. Switching DSP to 48MHz will save about 20mA.
Q: Do the UACB support Linux
A: Since Linux Kernelversion 2.6 ALSA removes the OSS-Architecture. The UACB is using
the ALSA interface for USB Audio.
To use “SET_MEM” and “GET_MEM” there is no filterdriver necessary you can do it
like described in the following documentation:
https://service.micronas.com/workgroups/Application%20Support/IPTV-
PC%20Media/Product%20Workgroups/UAC35xxB/Software/Code%20samples/Linux/
Q: Do Micronas GmbH will give us a Linux driver for UACB
A: If the Linux Distribution supports USB standard Audio, the UACB will work. If the
USB standard Audio is not supported by the Linux kernel you have to compile your
own. Every Linux Distribution has similarly driver, but they are not compatible.
We will not give a driver to each Distribution.
In no event shall Micronas be liable for indirect, incidental, consequential, punitive, special or other damages whatsoever including without limitation,
damages for loss of business profits, business interruption, loss of business information, and the like, arising out of or relating to the use of or the
inability to use the Application
Note, even if Micronas has been advised of the possibility of such damages, except personal injury or death resulting from Micronas’ negligence.
G
S Last changes: 07.05.2007

Q: Do the UACB supports Mac OS
A: Since MAC OS 10.xx the UACB will work with Mac OS. We do not guaranty that the
UACB will also work with Mac OS 9.xx.
FAQ’s
Q: I see that the UACB has 12 GPIO Pins how I can get access over USB from a Windows
application
A: You will find sample code in our service area under:
UAC35xxB > Software > Code samples > Windows
Q: Which of the 12 GPIO pins are used by the internal firmware
A: Codec Firmware:
GPIO 0 = Main output Vol. up
GPIO 1 = Main output Vol. down
GPIO 2 = Main output Mute toggle
GPIO 3 = Bass-Boost
GPIO 4 = Mic Mute (not visible on windows side).
GPIO 10 = High at start-up = No HID => all GPIO inputs above without function!
Headset Firmware:
GPIO 0 = Main output Vol. up
GPIO 1 = Main output Vol. down
GPIO 2 = Main output Mute On-off toggle
GPIO 3 = Bass-Boost
GPIO 4 = Mic Mute (not visible on windows side).
GPIO 5 = High at start-up = No HID => all GPIO inputs above without function!
Q: How can I switch off the HID functionality (e.g. Vol. up/down, Mute) via GPIO’s
because I need the GPIO’s for something else
A: Connect GPIO 10 to DVDD (high) before you power up (USB enumeration) the device.
After USB enumeration you can remove the connection to GPIO 10. No HID descriptor
will be loaded.
UAC3556B G6 (codec ROM firmware) not working like described above.
UAC3556B G7 (codec ROM firmware) is working like described above.
UAC3576B H7 (codec ROM firmware) is working like described above.
Q: I'm reading I2C data from the bus and bridge it via UACB and USB to my Windows
application. I increased the I2C bus speed from 100KHz to 400KHz but see no speedup.
A: the I2C limitations are on the USB bus. Because our device will only support full
speed there are the following limitations:
Internal we communicate via Vendor specific requests (I2C) to pipe 0 with a FIFO
size of max 64Byte. This means in max you can
read/write one I2C package of max. 64Byte in 1ms on a UHCI controller (512KBit/s)
or
read/write 13 I2C package of max. 64Byte in 1ms on an OHCI controller (6.6MBit/s).
Because most I2C commands will only have some bytes you will never reach the
400KHz clock speed via USB.
The only quick solution is to use an OHCI to speed up your I2C read/write.
In no event shall Micronas be liable for indirect, incidental, consequential, punitive, special or other damages whatsoever including without limitation,
damages for loss of business profits, business interruption, loss of business information, and the like, arising out of or relating to the use of or the
inability to use the Application
Note, even if Micronas has been advised of the possibility of such damages, except personal injury or death resulting from Micronas’ negligence.
G
S Last changes: 07.05.2007

FAQ’s
Q: I want to use 3 or more UACB chips behind a high speed hub, but only 2 devices are
working (recording and playback at the same time).
A: You need to use a so called Multi-TT (transaction translator) Hub. Hubs with a
single transaction translator share a single full speed connection (12MHz) for all
connected full speed devices, so you are running out of USB bandwith. This also
happens with a full speed hub.
Q: I have to use a single transaction translator or full speed hub, and want to
connect multiple UACB chips. To prevent running out of USB bandwith, I want to
reduce the sample frequency. How can I do this
A: You can reduce “HI_SAMPLE_FREQ” and “USB_FS_MAX” to a lower sample rate, but
Windows OS is calculating the USB bandwith from the “MaxPacketSize”, so you have
to reduce the Packet size too (in proportion to the sample frequency) to have the
wanted effect.
In no event shall Micronas be liable for indirect, incidental, consequential, punitive, special or other damages whatsoever including without limitation,
damages for loss of business profits, business interruption, loss of business information, and the like, arising out of or relating to the use of or the
inability to use the Application
Note, even if Micronas has been advised of the possibility of such damages, except personal injury or death resulting from Micronas’ negligence.
G
S Last changes: 07.05.2007