0. Project Inventory¶
This is the eight-active-package assisted-loader design, excluding the power diode. No PLD, PLD programmer, address expander, or reset transistor is needed. Match the complete part number and PDIP package before ordering.
Tick an item when you have the full listed quantity available, including the specified socket or headers where applicable. These are inventory checks, not installation or electrical-test results. Progress is saved in this browser on this device, separately from the implementation-phase checklists.
Semiconductors and Sockets¶
| Done | Qty | Reference | Part | Package / socket | Role |
|---|---|---|---|---|---|
| 1 | A1 | Raspberry Pi Pico 2 W | Soldered 2x20 headers; two socket strips | Supervisor, injected loading, USB, Wi-Fi, flash disks | |
| 1 | U1 | Z84C0020PEC | DIP-40, 15.24 mm wide socket | Fully static CMOS Z80 | |
| 1 | U2 | AS6C1008-55PCN | DIP-32, 15.24 mm wide socket | 128 KiB SRAM, two 64 KiB banks | |
| 1 | U3 | SN74HCT32N | DIP-14, 7.62 mm socket | Three fixed OR gates | |
| 1 | U4 | SN74AHCT244N | DIP-20, 7.62 mm socket | Clock and SRAM-control translation | |
| 1 | U7 | SN74LVC244AN | DIP-20, 7.62 mm socket | Eight 5 V-tolerant monitor inputs | |
| 1 | U9 | SN74AHCT245N | DIP-20, 7.62 mm socket | Pico-to-Z80 data | |
| 1 | U10 | SN74LVC245AN | DIP-20, 7.62 mm socket | Z80-to-Pico data | |
| 1 | D1 | 1N5819 | DO-41 axial | External +5 V to Pico VSYS |
Do not interchange AHCT, AHC, HCT, HC, or LVC parts. Pico headers must be soldered, not merely pushed through unsoldered holes. U5/U6/U8 are not fitted; reference gaps retain continuity with existing project labels.
Status Display Module¶
The Phase 10 status display is an external module, not one of the eight active packages. It connects to J2's 3.3 V I2C pins.
| Done | Qty | Reference | Part | Size / connector | Role |
|---|---|---|---|---|---|
| 1 | A2 | 0.91-inch 128x32 I2C OLED module, SSD1315 controller, white or blue | 38.00 x 12.00 mm board; 30.00 mm panel; 22.38 x 5.58 mm active area; 4-pin 2.54 mm header | Status display: IP address, uptime, heartbeat and web-terminal connection dot |
The header order is GND, VCC, SCK, SDA, with GND first. Many similar
modules put VCC first, so wire by the printed labels. The module prints SCK
for the I2C clock (SCL); some product drawings label the same pin SCL. The
module carries its own 3.3 V regulator and 4.7 kOhm I2C pull-ups and answers
at I2C address 0x3C. Supply it from the Pico's 3.3 V on J2.
Passive Components¶
| Done | Qty | Item | Purpose |
|---|---|---|---|
| 7 | 100 nF ceramic, at least 10 V | One per DIP IC | |
| 3 | 22 uF, at least 10 V | One +5 V bulk capacitor per board | |
| 1 | 100 uF, at least 10 V | Supply-entry bulk | |
| 40 | Individual 10 kOhm resistors | 16 address pull-ups, eight Pico data pull-downs, eight CPU control pull-ups, eight startup pulls | |
| Test only | 1 kOhm discrete | Manual input and first-drive current limiting |
Permanent breadboard resistors¶
Use 40 individual (discrete) 10 kOhm resistors. No resistor-network packages are fitted on the breadboard. Each resistor connects one signal to its specified supply rail or GND; signal wires must not be joined together. A resistor to a supply is a pull-up, and a resistor to GND is a pull-down. These establish defaults when no active output drives a signal.
The group checks below divide the same 40 resistors listed above; they are not additional parts. Tick each group when its quantity is set aside.
| Done | Quantity | Signals | Other end of each resistor |
|---|---|---|---|
| 16 | Address A0-A15, one resistor per bit | +5 V | |
| 8 | Pico data GP10-GP17, one resistor per bit | GND | |
| 8 | BUSREQ#, BUSACK#, MREQ#, IORQ#, RD#, WR#, INT#, NMI# | +5 V | |
| 4 | Pico GP4, GP5, GP6, GP7 startup controls | +3.3 V | |
| 4 | Pico GP2, GP3, GP8, GP9 startup controls | GND | |
| 40 | Total permanent resistors |
Install all permanent resistors in Phase 0, following the installation table. This is before fitting any active devices.
Temporary test resistors are additional bench items, not part of the 40 permanent branches. Later phases specify when to fit and remove 1 kOhm test resistors and extra 10 kOhm data-pattern pulls. Keep spares for those tests. No 4.7 kOhm or 47 kOhm reset-transistor parts remain.
Construction and Equipment¶
| Done | Qty | Item | Requirement / purpose |
|---|---|---|---|
| 3 | BB830 breadboards | 830-point boards | |
| As needed | Hookup wire | Short 22 AWG solid-core connections | |
| 1 | Regulated +5 V supply | Rated at least 1 A, with adjustable current limiting | |
| 1 | J1, TYPE-C USB-to-pin female breakout module | 21.6 x 12.7 mm PCB body; 6-pin single-row 2.54 mm header, 12.7 mm hole-centre span; pads CC2, D+, D-, CC1, GND, VBUS; 5 V supply-entry wiring; not a regulator | |
| 1 | USB data cable | Pico programming and diagnostics; not a charge-only cable | |
| 1 | Emergency supply disconnect | Accessible means to disconnect external power | |
| 1 | Multimeter | Continuity, resistance and rail-voltage checks | |
| 1 | DHO814 scope | Analog signal and timing measurements | |
| 1 | DSLogic Plus | Digital bus captures | |
| As needed | Spare capacitors, wire and 10 kOhm test resistors | Replacement parts and temporary data-pattern pulls | |
| 1 | IC extractor | Socketed device removal |
External +5 V must precede USB; remove USB before external +5 V. Fitted AHCT245 data ports are not power-off-safe. See the power phase.
Bill of Materials — Pricing and Suppliers¶
The dated price estimate below covers the earlier 39-resistor build; the current banked build adds R24 (one 10 kOhm resistor at Pico pin 11).
Prices checked on 24 October 2026, in USD from digikey.com except the user-supplied AliExpress Z80 price below and the Amazon Australia breadboards, excluding shipping, tax, and any tariffs. These are the displayed catalogue prices, not a quotation; recheck price and stock before ordering. Unit prices use the quantity-one tier except the 39 resistors, which use the 25-piece tier. Line totals are rounded to cents. Links identify the priced ordering option.
The Z80 listing costs AU$9.29 for two, as supplied by the project owner. Using 1 AUD = 0.70156 USD on 24 October 2026, that is approximately US$6.52 per two-pack, or US$3.26 per CPU. The BOM allocates one CPU to this build; purchasing the pack leaves one spare. Select the specified Z84C0020PEC DIP-40 variant. The AliExpress price was provided by the project owner and could not be independently checked.
The breadboards were purchased from Amazon Australia using the linked listing. The supplied price and screenshot show AU$10.20 per BB830. At the same exchange rate used above, this is approximately US$7.16 each, or AU$30.60 / US$21.47 for three. The three-board total uses the unrounded currency conversion before rounding to cents.
Sockets and Pico headers are priced separately below, although the inventory checks above group them with their devices. Passive components and connectors without a specified manufacturer use the listed through-hole ordering examples. The Pico needs two separate 1x20 male headers, one along each side, plus two matching socket strips.
Base circuit and breadboard construction¶
| Qty | Component / use | Supplier / ordering option | Unit (USD) | Line total (USD) |
|---|---|---|---|---|
| 1 | A1 Raspberry Pi Pico 2 W, without headers | SC1633 — 2648-SC1633CT-ND | $7.00 | $7.00 |
| 1 kit | A1 pair of 1x20 male headers | SparkFun 17907 — 1568-17907-ND | $1.59 | $1.59 |
| 2 | A1 1x20, 2.54 mm socket strips | Würth 61302011821 — 732-61302011821-ND | $0.88 | $1.76 |
| 1 | U1 Z84C0020PEC, DIP-40 | AliExpress two-pack; not stocked by DigiKey | ~$3.26 | ~$3.26 |
| 1 | U2 AS6C1008-55PCN, DIP-32 | 1450-1017-ND | $9.37 | $9.37 |
| 1 | U3 SN74HCT32N, DIP-14 | 296-1615-5-ND | $0.99 | $0.99 |
| 1 | U4 SN74AHCT244N, DIP-20 | 296-4723-5-ND | $1.24 | $1.24 |
| 1 | U7 SN74LVC244AN, DIP-20 | 296-8501-5-ND | $1.18 | $1.18 |
| 1 | U9 SN74AHCT245N, DIP-20 | 296-1476-5-ND | $1.12 | $1.12 |
| 1 | U10 SN74LVC245AN, DIP-20 | 296-8503-5-ND | $1.83 | $1.83 |
| 1 | U1 DIP-40 socket, 15.24 mm row spacing | On Shore ED40DT — ED3048-5-ND | $2.95 | $2.95 |
| 1 | U2 DIP-32 socket, 15.24 mm row spacing | On Shore ED32DT — ED3053-5-ND | $0.97 | $0.97 |
| 1 | U3 DIP-14 socket, 7.62 mm row spacing | On Shore ED14DT — ED3045-5-ND | $0.52 | $0.52 |
| 4 | U4/U7/U9/U10 DIP-20 sockets, 7.62 mm row spacing | On Shore ED20DT — ED3054-5-ND | $1.85 | $7.40 |
| 1 | D1 1N5819 Schottky diode, DO-41 | Diodes Inc. 1N5819-T — 1N5819DICT-ND | $0.59 | $0.59 |
| 7 | 100 nF ceramic, 50 V, X7R, radial | Vishay K104K15X7RF5TL2 — BC1084CT-ND | $0.31 | $2.17 |
| 3 | 22 uF electrolytic, 25 V, radial | Panasonic ECA-1EM220 — P5149-ND | $0.23 | $0.69 |
| 1 | 100 uF electrolytic, 25 V, radial | Panasonic ECA-1EM101B — 10-ECA-1EM101BCT-ND | $0.33 | $0.33 |
| 39 | Permanent 10 kOhm resistors, 1/4 W, 5%, axial | YAGEO CFR-25JB-52-10K | $0.03040 | $1.19 |
| 3 | BB830 830-point breadboards | Amazon Australia — B0040Z4QN8; purchased, AU$10.20 each | ~$7.16 | ~$21.47 |
| 1 kit | 22 AWG solid-core wire, six colours, 25 ft each | Adafruit 1311 — 1528-1743-ND | $15.95 | $15.95 |
| 1 | USB-A to Micro-B data cable, 1 m | Cvilux DH-20M50055 — 2987-DH-20M50055-ND | $1.58 | $1.58 |
Base subtotal: approximately $85.15 USD, including one Z80 and three Amazon breadboards. Buying the full Z80 two-pack brings the purchase subtotal to approximately $88.41 USD, including a spare CPU. The DigiKey-only subtotal is $60.42 USD. These include the full wire kit, sockets, headers, and USB cable. The subtotals exclude bench equipment, temporary test parts, spares, optional J2, shipping, tax, and tariffs.
Phase 10 status display¶
| Qty | Component / use | Supplier / ordering option | Unit (USD) | Line total (USD) |
|---|---|---|---|---|
| 1 | A2 0.91-inch 128x32 I2C OLED module, SSD1315, white or blue, 38 x 12 mm | AliExpress (HNX DIY); AU$4.54 | ~$3.19 | ~$3.19 |
The AU$4.54 single-unit price was supplied by the project owner and could not be independently checked; it converts at the same 24 October 2026 rate as the other AUD prices above. The status display is listed separately from the base subtotals: adding it brings the base build to approximately $88.34 USD, or approximately $91.60 USD with the full Z80 two-pack.
PCB Status¶
The revised schematic also includes J2, an optional 1x4, 2.54 mm expansion header for GP22, GP26, 3.3 V, and GND. Reserve one four-pin header for the PCB; it adds no active packages and is not required for the Phase 0-10 breadboard build. No peripheral pull-ups or LED resistors are included. See the expansion pin map.
The Phase 10 SSD1315 status OLED is schematic A2, wired through J2 on the breadboard and socketed in a 38 x 12 mm reservation on the PCB. It is not included in the core package count; see the status display module inventory and pricing.
The DIP PCB inventory owns the through-hole assembly: six bussed resistor arrays replace all 40 discrete pull resistors, J1 mounts the USB-C breakout on six soldered pins with only +5 V/GND wired, and four corner 2.7 mm holes accept M2.5 standoffs. The PCB's 20 MHz target requires its own qualification. J3 is an optional auxiliary power/probe header; use only one supply at a time. Keep the discrete-resistor inventory above for the breadboard build.
The partial-SMT inventory is separate: it uses SOIC logic, IS62C1024AL-35QLI SOP SRAM, individual 0603 pulls and an onboard USB-C receptacle. Compare both PCBs before ordering; their BOMs and assembly methods are not interchangeable.