Philips Semiconductors
P89LPC920/921/922/9221
8-bit microcontrollers with two-clock 80C51 core
Product data Rev. 08 — 15 December 2004 6 of 46
9397 750 14469
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
5.2 Pin description
Table 3: Pin description
Symbol Pin Type Description
P0.0 to P0.7 I/O Port 0: Port 0 is an 8-bit I/O port with a user-configurable output type. During reset
Port 0 latches are configured in the input only mode with the internal pull-up disabled.
The operation of Port 0 pins as inputs and outputs depends upon the port configuration
selected. Each port pin is configured independently. Refer to Section 8.12.1 “Port
configurations” and Table 8 “DC electrical characteristics” for details.
The Keypad Interrupt feature operates with Port 0 pins.
All pins have Schmitt triggered inputs.
Port 0 also provides various special functions as described below:
1 I/O P0.0 — Port 0 bit 0.
O CMP2 — Comparator 2 output.
I KBI0 — Keyboard input 0.
20 I/O P0.1 — Port 0 bit 1.
I CIN2B — Comparator 2 positive input B.
I KBI1 — Keyboard input 1.
19 I/O P0.2 — Port 0 bit 2.
I CIN2A — Comparator 2 positive input A.
I KBI2 — Keyboard input 2.
18 I/O P0.3 — Port 0 bit 3. High current source (P89LPC9221).
I CIN1B — Comparator 1 positive input B.
I KBI3 — Keyboard input 3.
17 I/O P0.4 — Port 0 bit 4. High current source (P89LPC9221).
I CIN1A — Comparator 1 positive input A.
I KBI4 — Keyboard input 4.
16 I/O P0.5 — Port 0 bit 5. High current source (P89LPC9221).
I CMPREF — Comparator reference (negative) input.
I KBI5 — Keyboard input 5.
14 I/O P0.6 — Port 0 bit 6. High current source (P89LPC9221).
O CMP1 — Comparator 1 output.
I KBI6 — Keyboard input 6.
13 I/O P0.7 — Port 0 bit 7. High current source (P89LPC9221).
I/O T1 — Timer/counter 1 external count input or overflow output.
I KBI7 — Keyboard input 7.
