AT89C51SND1C-ROTIL ATMEL Corporation, AT89C51SND1C-ROTIL Datasheet - Page 8

• Manufacturer Part Number: AT89C51SND1C-ROTIL
• Description: Single-Chip Microcontroller with MP3 Decoder and Man-Machine Interface
• Manufacturer: ATMEL Corporation

8
AT8xC51SND1C
Table 11. Keypad Interface Signal Description
Table 12. External Access Signal Description
Table 13. System Signal Description
Signal
Signal
Signal
Name
KIN3:0
Name
Name
AD7:0
A15:8
TST
RST
ALE
WR
ISP
RD
Type
Type
Type
I/O
I/O
I/O
O
O
O
I
I
I
Description
Keypad Input Lines
Holding one of these pins high or low for 24 oscillator periods triggers a
keypad interrupt.
Description
Address Lines
Upper address lines for the external bus.
Multiplexed higher address and data lines for the IDE interface.
Address/Data Lines
Multiplexed lower address and data lines for the external memory or the
IDE interface.
Address Latch Enable Output
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
This signal must be held to GND through a pull-down resistor at the
falling reset to force execution of the internal bootloader.
Read Signal
Read signal asserted during external data memory read operation.
Write Signal
Write signal asserted during external data memory write operation.
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
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
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
IL
is applied, whether or not the
V
DD
.
V
DD
.
4106F–8051–10/02
Alternate
Function
Alternate
Function
Alternate
Function
P1.3:0
P2.7:0
P0.7:0
P3.7
P3.6
-
-
-
-