Tiny Tapeout > Tiny Tapeout Chips > Tiny Tapeout 6 > 431 Dual Deque

431 Dual Deque

431 : Dual Deque

Author: Andrew Dona-Couch
Description: Dual byte-width double-ended queues
GitHub repository
GDS submitted
HDL project
Extra docs
Clock: 0 Hz

Two independent double-ended queues in one tiny footprint.

How it works

Each deque is an array of flip flops with a pointer to the top. The empty and full status flags for each are directly available on pins. The push and pop inputs as well as data bus lines are multiplexed using the deque select line.

Hold end_select low to operate as a stack. Tie end_select to push to operate as a queue.

How to test

To push (if full is low):

Put the data byte on data_in
Select which deque to push to with deque_select
Select which end to push to with end_select
Bring push high for one cycle

To pop (if empty is low):

Select which deque to push to with deque_select
Select which end to push to with end_select
Bring pop high for one cycle

To replace the last element of the deque (if empty is low):

Select which deque to push to with deque_select
Select which end to push to with end_select
Put the new data byte on data_in
Bring both push and pop high for one cycle

To read the end of the deque:

Select which deque to push to with deque_select
Select which end to push to with end_select
Wait one cycle
Read end of deque from data_out

External hardware

You would probably want to connect this to other devices that would find it useful.

IO

#	Input	Output	Bidirectional
0	Data In 0	Data Out 0	Deque Select
1	Data In 1	Data Out 1	End Select
2	Data In 2	Data Out 2	Push
3	Data In 3	Data Out 3	Pop
4	Data In 4	Data Out 4	Deque 0 Empty
5	Data In 5	Data Out 5	Deque 0 Full
6	Data In 6	Data Out 6	Deque 1 Empty
7	Data In 7	Data Out 7	Deque 1 Full

431 Dual Deque

431 : Dual Deque

How it works

How to test

External hardware

IO

Chip location