Zilog Z8F0411 Instrukcja Użytkownika Pobierz pdf (Strona 19)

MDS General-Purpose Board Development Kit

User Manual

UM016905-1207 MDS-GP Board Features

Keypad

Figure 7 displays the MDS-GP board with a 3 x 4 matrix keypad. The

keypad is controlled using GPIO port B. The four ROW pins have 10 K

pull-up resistors and are configured as inputs. The three COL pins are

configured as outputs. The software examples in this kit operate as

follows:

•

All ROW pins are configured as inputs, All COL pins are configured

as outputs and are initialized High.

•

In a interrupt routine, one COL pin is set Low and the ROW pins are

polled to check for a Low state.

•

If any ROW pin is polled Low, the key scan interrupt routine returns

the key pushed.

•

On each interrupt, a new COL pin is set Low. Three interrupts are

required to perform a full scan.

ZNEO

Z16F processor module requires minor changes for

keypad interfacing. See ZNEO

Z16F in Appendix—MDS-PM

Board Pin Maps on page 33.

Note:

1 2 ... 14 15 16 17 18 19 20 21 22 23 24 ... 82 83

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