de1_cl_controls

Files
file	bbc_micro_de1_cl.cdl
	BBC microcomputer with RAMs for the CL DE1 + daughterboard.

Detailed Description

Modules

module de1_cl_controls::de1_cl_controls	(	clock	clk,
		input bit	reset_n,
		output t_de1_cl_inputs_control	inputs_control,
		input t_de1_cl_inputs_status	inputs_status,
		output t_de1_cl_user_inputs	user_inputs,
		input bit	sr_divider[8]
	)

This module manages the buttons and other controls on the Cambridge University Computer Laboratory DE1 daughterboard.

A number of input switches are handled through a shift register, which is clocked using the input clock 'clk' divided down by the divider. This is handled by

The rotary encoder switch '318-ENC130175F-12PS' available from Mouser has the following operation:

Clockwise: B disconnects from C when A is disconnected from C

Counter-clockwise: B connects to C when A is disconnected from C

The CL daughterboard for the DE1 has a debounce RC network on the A and B pins, with a RC (probably) of 47us (high), so presumably the encoder is not optical :-).

Parameters

[in]	clk	system clock - not the shift register pin, something faster
[in]	reset_n	async reset
[out]	inputs_control	Signals to the shift register etc on the DE1 CL daughterboard
[in]	inputs_status	Signals from the shift register, rotary encoders, etc on the DE1 CL daughterboard
[out]	user_inputs
[in]	sr_divider	clock divider to control speed of shift register