AT83SND2C_05 Datasheet, PDF (8/235 Pages) ATMEL Corporation – Single-Chip Flash Microcontroller with MP3 Decoder with Full Audio Interface

Table 11. External Access Signal Description
Signal
Name
Type Description
A15:8
Address Lines
I/O Upper address lines for the external bus.
Multiplexed higher address and data lines for the IDE interface.
AD7:0
Address/Data Lines
I/O Multiplexed lower address and data lines for the external memory or the
IDE interface.
Address Latch Enable Output
ALE
O
ALE signals the start of an external bus cycle and indicates that valid
address information is available on lines A7:0. An external latch is used
to demultiplex the address from address/data bus.
ISP Enable Input (AT89C51SND2C Only)
ISP
I/O This signal must be held to GND through a pull-down resistor at the
falling reset to force execution of the internal bootloader.
RD
O
Read Signal
Read signal asserted during external data memory read operation.
WR
O
Write Signal
Write signal asserted during external data memory write operation.
EA⁽¹⁾
External Access Enable: EA must be externally held low to enable the
I
device to fetch code from external program memory locations 0000H to
FFFFH (RD).
Note: 1. For ROM/Flash/ROMless Dice product versions only.
Table 12. System Signal Description
Alternate
Function
P2.7:0
P0.7:0
-
-
P3.7
P3.6
-
Signal
Name
RST
TST
Type
I
I
Description
Reset Input
Holding this pin high for 64 oscillator periods while the oscillator is
running resets the device. The Port pins are driven to their reset
conditions when a voltage lower than V_IL is applied, whether or not the
oscillator is running.
This pin has an internal pull-down resistor which allows the device to be
reset by connecting a capacitor between this pin and V_DD.
Asserting RST when the chip is in Idle mode or Power-Down mode
returns the chip to normal operation.
Test Input
Test mode entry signal. This pin must be set to V_DD.
Alternate
Function
-
-
Table 13. Power Signal Description
Signal
Name
VDD
VSS
Type Description
PWR
Digital Supply Voltage
Connect these pins to +3V supply voltage.
GND
Circuit Ground
Connect these pins to ground.
Alternate
Function
-
-
8 AT8xC51SND2C
4341D–MP3–04/05