DESCRIPTION
This data sheet describes the 6 clock version of the 8xC554. This device is only available in 64L LQFP. The 8xC554 Single-Chip 8-Bit Microcontroller is manufactured in an advanced CMOS process and is a derivative of the 80C51 microcontroller family. The 87C554 has the same instruction set as the 80C51. Three versions of the derivative exist:

• 83C554—16k bytes ROM
• 80C554—ROMless version
• 87C554—16k bytes EPROM

FEATURES
• 80C51 central processing unit
• 16k ×8 EPROM expandable externally to 64k bytes
• An additional 16-bit timer/counter coupled to four capture registers and three compare registers
• Two standard 16-bit timer/counters
• 512 ×8 RAM, expandable externally to 64k bytes
• Capable of producing eight synchronized, timed outputs
• A 10-bit ADC with seven multiplexed analog inputs
• Fast 8-bit ADC option – 9 µS at 16 MHz
• Two 8-bit resolution, pulse width modulation outputs
• Five 8-bit I/O ports plus one 8-bit input port shared with analog inputs
• I2C-bus serial I/O port with byte oriented master and slave functions
• On-chip watchdog timer
• Extended temperature ranges
• Full static operation – 0 to 16 MHz
• Operating voltage range: 2.7 V to 5.5 V (0 to 8 MHz) and 4.5 V to 5.5 V (8 to 16 MHz)
   commercial temperature
• Security bits:
   – ROM – 2 bits
   – OTP/EPROM – 3 bits
• 4 level priority interrupt
• 15 interrupt sources
• Full-duplex enhanced UART
   – Framing error detection
   – Automatic address recognition
• Power control modes
   – Clock can be stopped and resumed
   – Idle mode
   – Power down mode
• Second DPTR register
• EMI reduction – 6 clock operation and ALE inhibit
• Programmable I/O pins
• Wake-up from power-down by external interrupts
• Software reset
• Power-on detect reset
• ADC charge pump disable
• ONCE mode
• ADC active in Idle mode