MS51FB9AE TSSOP20

8051-based CMOS microcontroller,  Voltage range: 2.4V to 5.5V
Runs up to 24 MHz, Features 16 K bytes flash, 1 K bytes SRAM, and 4 K bytes loader ROM for the ISP, also equipped with rich peripherals: 2 sets of UART; 1 set of I²C, and 1 set of SPI, 18 GPIO, 8 channels of 12-bit ADC, Watchdog Timer, Window Watchdog Timer and 6*16-bit PWM channel, package is available in TSSOP20.

Two 16-bit Timers / Counters 0 and 1 compatible with standard 8051
      -     One 16-bit Timer 2 with three-channel input capture module and 9 input pin can be selected
      -     One 16-bit auto-reload Timer 3, which can be the baud rate clock source of UARTs
      -     One 16-bit PWM counter interrupt for timer
      -     6*16-bit pulse width modulator ( PWM ) output, with different modes and Fault Brake function for motor control
      -     One programmable Watchdog Timer ( WDT )
      -     One dedicated Self Wake-up Timer ( WKT )
      -     2 full-duplex UART ports with frame error detection and automatic address recognition
      -     1 SPI port with master and slave modes, up to 12 Mbps when system clock is 24 MHz
      -     1 I²C bus with master and slave modes, up to 400 kbps data rate
      -     8 channels of 12-bit ADC, up to 500 ksps converting rate
      -     18 general purpose I / O pins and 1 input-only pin
      -     Programmable pull-ups pull-lows

   data sheet