PHONES Connector
The volume controlled sound is also available for driving stereo headphones (35mW @ 0db volume, 32
ohms) at the 3.5mm Stereo PHONES jack on the rear of the CFSound-IV.
NOTE: The common headphone output is not referenced to, and should not be
connected to Ground.
Pin #
Signal
TIP
Left
RING
Right
SLEEVE
Common
Remote Volume Connector
The sound volume level is controlled by two pushbuttons on the front of the CFSound-IV: one for Up
and one for Down. A momentary button press of the Up button raises the volume level, a button press of the
Down button lowers the volume level. Pressing and holding the button for ¼ second starts an automatic
volume increase/decrease until the button is released or the maximum/minimum volume is achieved. The
volume is essentially db linear in sixty-four, 1db increments from 0db → -66db.The current volume level is
‘remembered’ in non-volatile memory on the CFSound-IV and is restored to its last setting upon power-up.
The Up and Down button inputs are also available on the VOL connector along the front edge of the
printed circuit board inside the enclosure. Connecting a momentary button between the input and ground
parallels the operation of the on-board volume controls:
Pin #
Signal
1
DOWN-
2
GND
3
UP-
SD Card Connector
There are two slots for a SD and microSD memory card front of the CFSound-IV.
NOTE: Only one SD card slot may be in use at a time – simultaneous use of both a SD
and microSD memory card is NOT SUPPORTED.
All card accesses are performed in SPI mode using the following signals:
uSD Pin #
Signal Name
Description
1
DAT2 / NC
No connection
2
CD / DAT3 / CS-
Chip Select (active low)
3
CMD / DI
Data Input
4
VDD
Power (+3.3v)
5
CLK
Clock
6
VSS
Ground
7
DAT0 / DO
Data Output
8
DAT1 / RSV
No connection
SD or microSD cards of Standard Capacity (SDSC or SD, 1MB to 1GB) and High Capacity (SDHC,
2GB to 32GB) are supported.
