Entity: pmod_KYPD

File: pmod_KYPD.vhdl

Diagram

Description

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Authors: Patrick Lehmann

Entity: Digilent Peripherial Module: 4x4 Keypad (Pmod_KYPD)

Description:

This module drives a 4-bit one-cold encoded column vector to read back a 4-bit rows vector. By scanning column-by-column it's possible to extract the current button state of the whole keypad. This wrapper converts the high-active signals from :doc:PoC.io.KeypadScanner <../io_KeyPadScanner> to low-active signals for the pmod. An additional debounce circuit filters the button signals. The scan frequency and bounce time can be configured.

License:

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and

limitations under the License.

Generics

Generic name	Type	Value
CLOCK_FREQ	FREQ	100 MHz
SCAN_FREQ	FREQ	1 kHz
BOUNCE_TIME	time	10 ms

Ports

Port name	Direction	Type	Description
Clock	in	std_logic
Reset	in	std_logic
Keys	out	T_PMOD_KYPD_KEYPAD	Matrix interface
Columns_n	out	std_logic_vector(3 downto 0)	KeyPad interface
Rows_n	in	std_logic_vector(3 downto 0)

Signals

Name	Type	Description
ColumnVector	std_logic_vector(3 downto 0)
RowVector	std_logic_vector(3 downto 0)
KeyPadMatrix	T_SLM(3 downto 0, 3 downto 0)
KeyPadMatrix_slv	std_logic_vector(15 downto 0)
KeyPadVector	std_logic_vector(15 downto 0)
KeyPad	T_SLM(3 downto 0, 3 downto 0)

Instantiations

scanner: PoC.io_KeyPadScanner

Description
initialize a 4x4 matrix scanner

debounce: PoC.io_Debounce