General description
The P89LPC933/934/935/936 is a single-chip microcontroller, available in low cost packages, based on a high performance processor architecture that executes instructions in two to four clocks, six times the rate of standard 80C51 devices. Many system-level functions have been incorporated into the P89LPC933/934/935/936 in order to reduce component count, board space, and system cost.

Features
Principal features
■ 4 kB/8 kB/16 kB byte-erasable flash code memory organized into 1 kB/2 kB sectors
   and 64-byte pages. Single-byte erasing allows any byte(s) to be used as non-volatile
   data storage.
■ 256-byte RAM data memory. Both the P89LPC935 and P89LPC936 also include a
   512-byte auxiliary on-chip RAM.
■ 512-byte customer data EEPROM on chip allows serialization of devices, storage of
   setup parameters, etc. (P89LPC935/936).
■ Dual 4-input multiplexed 8-bit A/D converters/DAC outputs (P89LPC935/936, single
   A/D on P89LPC933/934).Two analog comparators with selectable inputs and
   reference source.
■ Two 16-bit counter/timers (each may be configured to toggle a port output upon timer
   overflow or to become a PWM output) and a 23-bit system timer that can also be used
   as an RTC.
■ Enhanced UART with fractional baud rate generator, break detect, framing error
   detection, and automatic address detection; 400 kHz byte-wide I2C-bus
   communication port and SPI communication port.
■ Capture/Compare Unit (CCU) provides PWM, input capture, and output compare
   functions (P89LPC935/936).
■ High-accuracy internal RC oscillator option allows operation without external oscillator
   components.The RC oscillator option is selectable and fine tunable.
■ 2.4 V to 3.6 V VDD operating range. I/O pins are 5 V tolerant (may be pulled up or
   driven to 5.5 V).
■ 28-pin TSSOP, PLCC, and HVQFN packages with 23 I/O pins minimum and up to 26
   I/O pins while using on-chip oscillator and reset options.
  
Additional features
■ A high performance 80C51 CPU provides instruction cycle times of 111 ns to 222 ns
   for all instructions except multiply and divide when executing at 18 MHz. This is six
   times the performance of the standard 80C51 running at the same clock frequency. A
   lower clock frequency for the same performance results in power savings and reduced
   EMI.
■ Serial flash In-Circuit Programming (ICP) allows simple production coding with
   commercial EPROM programmers. Flash security bits prevent reading of sensitive
   application programs.
■ Serial flash In-System Programming (ISP) allows coding while the device is mounted
   in the end application.
■ In-Application Programming (IAP) of the flash code memory. This allows changing the
   code in a running application.
■ Watchdog timer with separate on-chip oscillator, requiring no external components.
   The watchdog prescaler is selectable from eight values.
■ Low voltage reset (brownout detect) allows a graceful system shutdown when power
   fails. May optionally be configured as an interrupt.
■ Idle and two different power-down reduced power modes. Improved wake-up from
   Power-down mode (a LOW interrupt input starts execution). Typical power-down
   current is 1 µA (total power-down with voltage comparators disabled).
■ Active-LOW reset. On-chip power-on reset allows operation without external reset
   components. A reset counter and reset glitch suppression circuitry prevent spurious
   and incomplete resets. A software reset function is also available.
■ Configurable on-chip oscillator with frequency range options selected by user
   programmed flash configuration bits. Oscillator options support frequencies from
   20 kHz to the maximum operating frequency of 18 MHz.
■ Oscillator fail detect. The watchdog timer has a separate fully on-chip oscillator
   allowing it to perform an oscillator fail detect function.
■ Programmable port output configuration options: quasi-bidirectional, open drain,
   push-pull, input-only.
■ Port ‘input pattern match’ detect. Port 0 may generate an interrupt when the value of
   the pins match or do not match a programmable pattern.
■ LED drive capability (20 mA) on all port pins. A maximum limit is specified for the
   entire chip.
■ Controlled slew rate port outputs to reduce EMI. Outputs have approximately 10 ns
   minimum ramp times.
■ Only power and ground connections are required to operate the
   P89LPC933/934/935/936 when internal reset option is selected.
■ Four interrupt priority levels.
■ Eight keypad interrupt inputs, plus two additional external interrupt inputs.
■ Schmitt trigger port inputs.
■ Second data pointer.
■ Emulation support.