EM6603

03/02 REV. G/439

Copyright

 2001, EM Microelectronic-Marin SA

9

www.emmicroelectronic.com

6

INPUT and OUTPUT ports

The EM6603 has four independent 4-bit ports, as shown in Table 9

Table 9.Input / Output Ports Overview

Port

Mode

Mask Options

Function(s)

PA(0:3)

Input

Pull-Up/Down

(*)Debouncer

(*) + or – IRQ edge

RESET combination

Input Interrupt

Software Test Variable

PA3 input for event counter

RESET input(s)

PB(0:3)

Individual

input or output

Nch open drain output

Pull-Up/Down on input

Input or Output

PB0 for buzzer output

PC(0:3)

Port input or output

Pull-Up/Down

(*)+ or – IRQ edge

(*)Debouncer

Nch open drain output

Input or Output Port

Interrupt

PD(0:3)

Port input or Output

Pull-Up/Down on Input

Nch open drain output

Input or Output Port

PD0 -SWB serial clock output

PD1 -SWB serial data output

(*) Some options can be set also by Option register .

Table 10.Option register - Option

Bit

Name

Reset

R/W

Description

3

IRQedgeR

0

R/W

Rising edge interrupt for portA&C

2

debPCN

0

R/W

PortC without/with debouncer

1

debPAN

0

R/W

PortA without/with debouncer

0

NoWD

0

R/W

WatchDog timer Off

IRQedgeR - Valid for both PortA and PortC input interrupt edge. At RESET it is cleared to 0 selecting the falling

edge at the input as the interrupt source. When set to 1 the rising edge is active. (option 3 on Fig 6 and Fig 8)

debPAN - by default after reset it is 0 enabling the debouncers on whole portA. Writing it to 1 removes the

debouncers from the PortA. (option 2 on Figure 6)

debPCN - by default after reset it is 0 enabling the debouncers on whole portC. Writing it to 1 removes the

debouncers from the PortC. (option 2 on Figure 8)

NoWD - by default after reset it is 0 = Watchdog timer is On. Writing it to 1 removes the WatchDog timer.

6.1 PortA

The EM6603 has one four bit general purpose input port. Each of the input port terminals PA3..PA0 has an

internal pull-Up/Down resistor which can be selected with mask options. Port information is read directly from

the pin into a register.

On inputs PA0, PA1, PA2 and PA3 debouncers for noise rejection are added by default. For interrupt

generation, one can choose between either direct input or debounced input. With the debPAN bit at 0 in the

Option register all the PortA inputs are debounced and with the debPAN bit at 1 none of the PortA inputs are

debounced. With the debouncer selected the input must be stable for two rising edges of 1024Hz or 128Hz

clocks (at 32kHz). This corresponds to a worst case of 1.95ms or 15.62msec. PortA terminals PA0, PA1 and

PA2

are also used as input conditions for conditional software branches as shown on the next page: