AT87C52X2-RLTUM Atmel, AT87C52X2-RLTUM Datasheet - Page 28

• Manufacturer Part Number: AT87C52X2-RLTUM
• Description: IC 8051 MCU 8K OTP 40MHZ 44VQFP
• Manufacturer: Atmel
• Series: 87Cr

Specifications of AT87C52X2-RLTUM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40/20MHz
• Connectivity: UART/USART
• Peripherals: POR
• Number Of I /o: 32
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: OTP
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -

ONCE
Emulation)
28
TM
TS8xCx2X2
Mode (ON Chip
The ONCE mode facilitates testing and debugging of systems using TS80C52X2 with-
out removing the circuit from the board. The ONCE mode is invoked by driving certain
pins of the TS80C52X2; the following sequence must be exercised:
•
•
While the TS80C52X2 is in ONCE mode, an emulator or test CPU can be used to drive
the circuit Table 26. shows the status of the port pins during ONCE mode.
Normal operation is restored when normal reset is applied.
Table 16. External Pin Status during ONCE Mode
Weak pull-
Pull ALE low while the device is in reset (RST high) and PSEN is high.
Hold ALE low as RST is deactivated.
ALE
up
Weak pull-
PSEN
up
Port 0
Float
Weak pull-
Port 1
up
Weak pull-
Port 2
up
Weak pull-
Port 3
up
4184G–8051–09/06
XTAL1/2
Active