tsc251g1dxxx-l12ced ATMEL Corporation, tsc251g1dxxx-l12ced Datasheet - Page 9

• Manufacturer Part Number: tsc251g1dxxx-l12ced
• Description: 8/16-bit Microcontroller With Serial Communication Interfaces - 32kbytes Rom
• Manufacturer: ATMEL Corporation

4135F–8051–11/06
Table 2. Product Name Signal Description (Continued)
Signal
Name
WAIT#
WCLK
XTAL1
T2EX
VSS1
VSS2
VDD
WR#
T1:0
TXD
VPP
VSS
T2
Type
PWR
GND
GND
GND
I/O
I/O
O
O
O
I
I
I
I
Description
Timer 1:0 External Clock Inputs
When timer 1:0 operates as a counter, a falling edge on the T1:0 pin
increments the count.
Timer 2 Clock Input/Output
For the timer 2 capture mode, T2 is the external clock input. For the Timer 2
clock-out mode, T2 is the clock output.
Timer 2 External Input
In timer 2 capture mode, a falling edge initiates a capture of the timer 2
registers. In auto-reload mode, a falling edge causes the timer 2 register to
be reloaded. In the up-down counter mode, this signal determines the
count direction: 1 = up, 0 = down.
Transmit Serial Data
TXD outputs the shift clock in serial I/O mode 0 and transmits data in serial
I/O modes 1, 2 and 3.
Digital Supply Voltage
Connect this pin to +5V or +3V supply voltage.
Programming Supply Voltage
The programming supply voltage is applied to this input for programming
the on-chip EPROM/OTPROM.
Circuit Ground
Connect this pin to ground.
Secondary Ground 1
This ground is provided to reduce ground bounce and improve power
supply bypassing. Connection of this pin to ground is recommended.
However, when using the TSC80251G2D as a pin-for-pin replacement for a
8xC51 product, VSS1 can be unconnected without loss of compatibility.
Not available on DIP package.
Secondary Ground 2
This ground is provided to reduce ground bounce and improve power
supply bypassing. Connection of this pin to ground is recommended.
However, when using the TSC80251G2D as a pin-for-pin replacement for a
8xC51 product, VSS2 can be unconnected without loss of compatibility.
Not available on DIP package.
Real-time Synchronous Wait States Input
The real-time WAIT# input is enabled by setting RTWE bit in WCON
(S:A7h). During bus cycles, the external memory system can signal
‘system ready’ to the microcontroller in real time by controlling the WAIT#
input signal.
Wait Clock Output
The real-time WCLK output is enabled by setting RTWCE bit in WCON
(S:A7h). When enabled, the WCLK output produces a square wave signal
with a period of one half the oscillator frequency.
Write
Write signal output to external memory.
Input to the on-chip inverting oscillator amplifier
To use the internal oscillator, a crystal/resonator circuit is connected to this
pin. If an external oscillator is used, its output is connected to this pin.
XTAL1 is the clock source for internal timing.
AT/TSC8x251G2D
Alternate
Function
P1.0
P1.1
P3.1
P1.6
P1.7
P3.6
–
–
–
–
–
–
–
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