COP425C datasheet(18/24 Pages) NSC

18 / 24 page

Power Dissipation (Continued)

If an IT instruction is executed the chip goes into the IDLE

mode until the timer overflows In IDLE mode the current

drain can be calculated from the following equation

IcieIQaVc40cFi

For example at 5 volts VCC and 400 kHz

Icie20a5c40c04e100 mA

The total average current will then be the weighted average

of the operating current and the idle current

Ita e ICO c

ToaTi

Ici c

ToaTi

where

Itaetotal average current

ICOeoperating current

Icieidle current

Toeoperating time

Tieidle time

IO OPTIONS

Outputs have the following optional configurations illustrat-

ed in

Figure 11

a Standard

A CMOS push-pull buffer with an N-channel

device to ground in conjunction with a P-channel device

to VCC compatible with CMOS and LSTTL

b Low Current

This is the same configuration as a

above except that the sourcing current is much less

c Open Drain

An N-channel device to ground only allow-

ing external pull-up as required by the user’s application

d Standard TRI-STATE L Output

A CMOS output buffer

similar to a which may be disabled by program control

e Low-Current TRI-STATE L Output

This is the same as

d above except that the sourcing current is much less

f Open-Drain TRI-STATE L Output

This has the N-chan-

nel device to ground only

All inputs have the following options

g Input with on chip load device to VCC

h Hi-Z input which must be driven by the users logic

When using either the G or L IO ports as inputs a pull-up

device is necessary This can be an external device or the

following alternative is available Select the low-current out-

put option Now by setting the output registers to a logic

‘‘1’’ level the P-channel devices will act as the pull-up load

Note that when using the L ports in this fashion the Q regis-

ters must be set to a logic ‘‘1’’ level and the L drivers MUST

BE ENABLED by an LEI instruction (see description above)

All output drivers use one or more of three common devices

numbered 1 to 3 Minimum and maximum current (IOUT and

VOUT) curves are given in Figure 12 for each of these de-

vices to allow the designer to effectively use these IO con-

figurations

a Standard Push-Pull Output

b Low Current Push-Pull Output

c Open-Drain Output

d Standard TRI-STATE ‘‘L’’ Output

e Low Current TRI-STATE

‘‘L’’ Output

f Open Drain TRI-STATE

‘‘L’’ Output

TLDD5259 – 14

g Input with Load

h Hi-Z Input

FIGURE 11 InputOutput Configurations

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