Philips Semiconductors
P89LPC924/925
8-bit microcontrollers with accelerated two-clock 80C51 core
Product data Rev. 03 — 15 December 2004 2 of 49
9397 750 14471
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
2.2 Additional features
■ 20-pin TSSOP package.
■ 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.
■ In-Application Programming of the Flash code memory. This allows changing the
code in a running application.
■ Serial Flash programming allows simple in-circuit production coding. Flash
security bits prevent reading of sensitive application programs.
■ 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.
■ 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 P89LPC924/925
when internal reset option is selected.
■ Four interrupt priority levels.
■ Eight keypad interrupt inputs, plus two additional external interrupt inputs.
■ Second data pointer.
■ Schmitt trigger port inputs.
■ Emulation support.
