Rainbow Electronics T89C5115 - Manual (Page 4)

4
T89C5115
4128A–8051–04/02
Table 1. Pin Description
Pin Name Type Description
VSS GND Circuit ground
VCC Supply Voltage
VAREF Reference Voltage for ADC
VAVCC Supply Voltage for ADC
VAGND Reference Ground for ADC
P1.0:7 I/O Port 1:
Is an 8-bit bi-directional I/O port with internal pull-ups. Port 1 pins can be used for
digital input/output or as analog inputs for the Analog Digital Converter (ADC). Port 1
pins that have 1’s written to them are pulled high by the internal pull-up transistors
and can be used as inputs in this state. As inputs, Port 1 pins that are being pulled
low externally will be the source of current (I
IL
, see section "Electrical Characteristic")
because of the internal pull-ups. Port 1 pins are assigned to be used as analog
inputs via the ADCCF register (in this case the internal pull-ups are disconnected).
As a secondary digital function, port 1 contains the Timer 2 external trigger and clock
input; the PCA external clock input and the PCA module I/O.
P1.0/AN0/T2
Analog input channel 0,
External clock input for Timer/counter2.
P1.1/AN1/T2EX
Analog input channel 1,
Trigger input for Timer/counter2.
P1.2/AN2/ECI
Analog input channel 2,
PCA external clock input.
P1.3/AN3/CEX0
Analog input channel 3,
PCA module 0 Entry of input/PWM output.
P1.4/AN4/CEX1
Analog input channel 4,
PCA module 1 Entry of input/PWM output.
P1.5/AN5
Analog input channel 5,
P1.6/AN6
Analog input channel 6,
P1.7/AN7
Analog input channel 7,
It can drive CMOS inputs without external pull-ups.
P2.0:7 I/O
Port 2:
Is an 2-bit bi-directional I/O port with internal pull-ups. Port 2 pins that have 1’s
written to them are pulled high by the internal pull-ups and can be used as inputs in
this state. As inputs, Port 2 pins that are being pulled low externally will be a source
of current (IIL, on the datasheet) because of the internal pull-ups.
In the T89C51CC02 Port 2 can sink or source 5 mA. It can drive CMOS inputs
without external pull-ups.