Zilog EZ80L92 Manual do Utilizador descarregar pdf (Página 29)

eZ80L92 Development Kit

User Manual

UM012913-0407 Operational Description

Reading from the general-purpose port can damage the drivers used for

the general-purpose port and memory. The port can, however, be used for

writing data.

LED Matrix

The one 7 x 5 LED matrix device on the eZ80Acclaim!

Development

Platform is a memory-mapped device that can be used to display informa-

tion, such as programmed alphanumeric characters. For example, the

LED display sample program that is shipped with this kit displays the

alphanumeric message:

eZ80

To illuminate any LED in the matrix, its respective anode bit must be set

to 1 and its corresponding cathode bit must be set to 0.

Bits 0–6 in Table 7 are LED anode bits. They must be set High (1) and

their corresponding cathode bits, bits 0–4 in Table 9, must be set Low (0)

to illuminate each of the LED’s, respectively.

Bit 7 in Table 7 does not carry any significance within the LED matrix. It

is used for the general-purpose port as a control bit.

Table 8. General-Purpose Port Data Register

Function/Bit # 76543210

GPIO D0 X

GPIO D1 X

GPIO D2 X

GPIO D3 X

GPIO D4 X

GPIO D5 X

GPIO D6 X

GPIO D7 X

Caution:

1 2 ... 24 25 26 27 28 29 30 31 32 33 34 ... 85 86

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