Signal
Name
Alternate
Function
Type
Description
Timer 1 Gate Input
INT1 serves as external run control for timer 1, when selected by
GATE1 bit in TCON register.
INT1
I
P3.3
External Interrupt 1
INT1 input sets IE1 in the TCON register. If bit IT1 in this register is set,
bit IE1 is set by a falling edge on INT1#. If bit IT1 is cleared, bit IE1 is
set by a low level on INT1#.
Timer 0 External Clock Input
T0
T1
I
I
When timer 0 operates as a counter, a falling edge on the T0 pin
increments the count.
P3.4
P3.5
Timer 1 External Clock Input
When timer 1 operates as a counter, a falling edge on the T1 pin
increments the count.
Table 4. Audio Interface Signal Description
Signal
Alternate
Function
Name
DCLK
DOUT
Type
O
Description
DAC Data Bit Clock
DAC Audio Data Output
-
-
O
DAC Channel Select Signal
DSEL is the sample rate clock output.
DSEL
SCLK
O
O
-
-
DAC System Clock
SCLK is the oversampling clock synchronized to the digital audio data
(DOUT) and the channel selection signal (DSEL).
Table 5. USB Controller Signal Description
Signal
Name
Alternate
Function
Type
I/O
Description
USB Positive Data Upstream Port
This pin requires an external 1.5 KΩ pull-up to VDD for full speed
operation.
D+
-
-
D-
I/O
USB Negative Data Upstream Port
Table 6. MutiMediaCard Interface Signal Description
Signal
Name
Alternate
Function
Type
Description
MMC Clock output
Data or command clock transfer.
MCLK
O
-
MMC Command line
Bidirectional command channel used for card initialization and data
transfer commands. To avoid any parasitic current consumption,
MCMD
MDAT
I/O
I/O
-
unused MCMD input must be polarized to VDD or VSS
.
MMC Data line
Bidirectional data channel. To avoid any parasitic current consumption,
unused MDAT input must be polarized to VDD or VSS
-
.
6
AT8xC51SND2C
4341D–MP3–04/05
ATMEL [ ATMEL ]
