HardLabs

RAM

Robert-Riordan-UCD·8_Bit_CPU_PCB·RAM/RAM.kicad_pcb

RAM PCB layout, top view — open source AVR/Arduino board by Robert-Riordan-UCD

About the RAM PCB

RAM is an open source AVR/Arduino PCB design by Robert-Riordan-UCD, published on GitHub under the CERN-OHL-P-2.0 license. It is a 2-layer board measuring 133 × 58.5 mm, with 57 components from 20 distinct parts.

Its main chip is the ATMEGA328-PU, from the AVR/Arduino family. Other key parts include the CD74HCT258E and SN74HCT245N. By type, the board carries 20 resistors, 9 connectors, 9 capacitors, 8 ICs, 8 diodes and 2 crystals.

It belongs with the dev boards & breakouts designs in this gallery.

From the project

PCB version of Ben Eaters 8-bit breadboard computer

This is my version of Ben Eaters 8-bit breadboard SAP-1 CPU, converted to a PCB. I have made some minor changes as I could not find all of the components as listed in Ben's part list.

1. RAM IC's have been replaced with ATMega328-PU's. This should allow me to have persistant programs between power cycles.

CERN Open Hardware Licence Version 2 - Permissive

Main components on the RAM

CD74HCT258ESN74HCT245NATMEGA328-PU

RAM bill of materials (BOM)

57 components, 20 distinct parts.

QtyPartRefs
1
~
U1
3
CD74HCT258E
U2, U4, U6
1
SN74HCT245N
U3
1
~
U5
2
ATMEGA328-PU
Microchip Technology
U7, U8
2
16MHz
Y1, Y2
2
Conn_01x02_Pin
J1, J3
2
Conn_01x01_Pin
J2, J4
1
Conn_01x05_Pin
J5
3
Conn_01x03_Pin
J6, J7, J8
1
Conn_01x10_Pin
J9
1
B3U-1000P
Omron Electronics Inc-EMC Div
S1
8
LED
D1, D2, D3, D4, D5, D6, D7, D8
1
0.01uF
C1
2
0.1uF
C2, C3
2
0.1uF
C4, C7
4
22pF
C5, C6, C8, C9
9
1k
R1, R10, R11, R12, R13, R14, R15, R16 +1
8
220
R2, R3, R4, R5, R6, R7, R8, R9
3
10k
R18, R19, R20

RAM design files

The KiCad project lives in the Robert-Riordan-UCD/8_Bit_CPU_PCB repository on GitHub; these links point at the commit this page was built from.

RAM: common questions

What microcontroller does the RAM use?

The RAM is built around the ATMEGA328-PU, from the AVR/Arduino family.

How big is the RAM PCB?

The RAM measures 133 × 58.5 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the RAM?

57 components, from 20 distinct parts. The full bill of materials is listed on this page.

Where can I download the RAM design files?

From the Robert-Riordan-UCD/8_Bit_CPU_PCB repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the RAM design in my own project?

Yes, under the terms of its CERN-OHL-P-2.0 license, which Robert-Riordan-UCD chose for the repository.

Can I test firmware for the RAM without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug AVR/Arduino firmware against it before you order a PCB.

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