TS87C54X2-VCB Atmel, TS87C54X2-VCB Datasheet - Page 9

• Manufacturer Part Number: TS87C54X2-VCB
• Description: IC MCU 8BIT 16K OTP 40MHZ 44PLCC
• Manufacturer: Atmel
• Series: 87Cr

Specifications of TS87C54X2-VCB

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40/30MHz
• Connectivity: UART/USART
• Peripherals: POR, WDT
• Number Of I /o: 32
• Program Memory Size: 16KB (16K 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: 0°C ~ 70°C
• Package / Case: 44-PLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

Figure 6-2.
4431E–8051–04/06
XTAL1
XTAL1:2
X2 bit
CPU clock
Mode Switching Waveforms
STD Mode
The X2 bit in the CKCON register (See Table 6-1.) allows to switch from 12 clock cycles per
instruction to 6 clock cycles and vice versa. At reset, the standard speed is activated (STD
mode). Setting this bit activates the X2 feature (X2 mode).
CAUTION
In order to prevent any incorrect operation while operating in X2 mode, user must be aware that
all peripherals using clock frequency as time reference (UART, timers) will have their time refer-
ence divided by two. For example a free running timer generating an interrupt every 20 ms will
then generate an interrupt every 10 ms. UART with 4800 baud rate will have 9600 baud rate.
X2 Mode
AT/TS8xC54/8X2
STD Mode
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