Mega IIe
About the Mega IIe PCB
Mega IIe is an open source RP2040/RP2350 PCB design by baldengineer, published on GitHub under the MIT license. It is a 4-layer board measuring 163 × 174.4 mm, with 307 components from 125 distinct parts.
Its main chip is the RP2040, from the RP2040/RP2350 family. Other key parts include the Apple_MEGA_II, w65c02s, 74LVC1G02, 74HC245 and AT28C256-PLCC. By type, the board carries 96 resistors, 92 capacitors, 35 ICs, 27 diodes, 23 connectors and 10 transistors.
From the project
Using the Mega II from a IIgs to make a Apple IIe compatible computer: The Mega IIe!
The Proto PCBs are boards to prototype an IIe from the IIgs ASICs. Eventually, these will be condensed to a single board.
It connects to both the VGC and 6502 boards. The VGC connects with a 40-pin cable, like an IDE cable. The 6502 connects with a couple of ribbon cables.
The VGC also generates the 14 MHz clock from a 28 MHz oscilliator. (It is not clear yet which clocks the MEGA-II generates and which the VGC does.)
Main components on the Mega IIe
Mega IIe bill of materials (BOM)
307 components, 125 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | Apple_MEGA_II | PLCC-84_THT-Socket | U1 |
| 1 | w65c02s | TQFP-44_10x10mm_P0.8mm | U2 |
| 1 | 74LVC1G02 | SOT-23-5 | U3 |
| 3 | 74HC245 | SOIC-20W_7.5x12.8mm_P1.27mm | U4, U5, U13 |
| 1 | AT28C256-PLCC | PLCC-32_11.4x14.0mm_P1.27mm | U6 |
| 4 | DRAM64KX4 | DIP-18_W7.62mm_Socket_LongPads | U7, U8, U9, U10 |
| 1 | IWM | PLCC-28_THT-Socket | U11 |
| 1 | Slotmaker | PLCC-44_THT-Socket | U12 |
| 2 | RP2040 | RP2040-QFN-56 | U14, U23 |
| 2 | MIC5504-3.3YM5 | SOT-23-5 | U15, U34 |
| 1 | 74HC245 | SO-20_5.3x12.6mm_P1.27mm | U16 |
| 2 | W25Q128JVS | SOIC-8_5.23x5.23mm_P1.27mm | U17, U19 |
| 1 | 74HCT251D,652 HCT251 | SOIC-16_3.9x9.9mm_P1.27mm | U18 |
| 2 | NE556 | SO-14_3.9x8.65mm_P1.27mm | U20, U21 |
| 1 | 74HCT245 | SO-20_5.3x12.6mm_P1.27mm | U22 |
| 4 | 74LVC2G04 | SOT-23-6 | U24, U29, U30, U35 |
| 2 | SN74LVC573ANS | SO-20_5.3x12.6mm_P1.27mm | U25, U28 |
| 1 | MCP4541T | MSOP-8_3x3mm_P0.65mm | U26 |
| 1 | LM4875 | SOIC-8_3.9x4.9mm_P1.27mm | U27 |
| 2 | 74LVC2G04-2040 | SOT-23-6 | U31, U33 |
Show 105 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | LM7905_TO220 | TO-220-3_Vertical | U32 |
| 8 | BC817 | SOT-23 | Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q10 |
| 2 | MMBT3906 | SOT-23 | Q8, Q9 |
| 1 | MCSJK-6NC1-14.31818-25-B 14.31818MHz | Oscillator_SMD_EuroQuartz_XO91-4Pin_7.0x5.0mm | X1 |
| 2 | ECS-120-18-33-JEM-TR | Crystal_SMD_3225-4Pin_3.2x2.5mm | Y1, Y2 |
| 1 | XY | PinHeader_2x02_P2.54mm_Vertical | J1 |
| 1 | DB19_4 | PinHeader_1x02_P2.54mm_Vertical-LOCK | J2 |
| 1 | DB19_16 | PinHeader_1x02_P2.54mm_Vertical-LOCK | J3 |
| 3 | EN | PinHeader_1x03_P2.54mm_Vertical-LOCK | J4, J7, J8 |
| 1 | DSUB19 | DSUB-19_Apple_II_Floppy | J5 |
| 1 | FDC Hdr | PinHeader_2x10_P2.54mm_Vertical | J6 |
| 1 | IO-Xtra | PinHeader_1x03_P2.54mm_Vertical | J9 |
| 1 | Apple_II_Slot | Sullins-EBC25DCWN-Edge Socket 50 pos (25x2) 0.100 | J10 |
| 1 | Game Port | DIP-16_W7.62mm_Socket | J11 |
| 1 | Right Angle | TE 5650118-3 Right Angle 12 Pos Socket | J12 |
| 1 | SWD | SAMTEC_FTSH-105-XX-X-DV | J13 |
| 1 | USB1125-GF-B USB_A | USB_A_GCT_USB1125 | J14 |
| 1 | PS Aux | PinHeader_1x05_P2.54mm_Vertical | J15 |
| 1 | PS Control | PinHeader_1x03_P2.54mm_Vertical | J16 |
| 1 | VGA_Micro | USB_Micro-B_GCT_USB3076-30-A | J17 |
| 1 | vga_SWD | SAMTEC_FTSH-105-XX-X-DV | J18 |
| 1 | SPKR | PinHeader_1x02_P2.54mm_Vertical | J19 |
| 1 | 54-00178 Ears | Jack_3.5mm_tensility_54-00177 | J20 |
| 1 | KBD Serial | PinHeader_1x03_P2.54mm_Vertical | J21 |
| 1 | L77HDE15SD1CH4F | AMPHENOL_L77HDE15SD1CH4F | J22 |
| 1 | KBD_L_HDR | PinHeader_1x02_P2.54mm_Vertical | J24 |
| 1 | Int-Ser1 | SolderJumper-3_P2.0mm_Open_TrianglePad1.0x1.5mm_NumberLabels | JP1 |
| 1 | Int-Ser2 | SolderJumper-3_P2.0mm_Open_TrianglePad1.0x1.5mm_NumberLabels | JP2 |
| 1 | Vbus_2040 | SolderJumper-2_P1.3mm_Open_TrianglePad1.0x1.5mm | JP3 |
| 2 | 4k7 | R_0603_1608Metric | RDNP1, RDNP2 |
| 2 | 4k7 | R_0805_2012Metric | RNP1, RNP2 |
| 1 | 1k | R_0805_2012Metric | RNP3 |
| 1 | MEGA RESET | SW_SPST_PTS810 | SW1 |
| 1 | DEV | SW_DIP_SPSTx08_Slide_Omron_A6H-8101_W6.15mm_P1.27mm | SW2 |
| 1 | IOSEL | SW_DIP_SPSTx08_Slide_Omron_A6H-8101_W6.15mm_P1.27mm | SW3 |
| 1 | KBD RESET | SW_SPST_PTS810 | SW4 |
| 1 | KBD Boot Sel | SW_SPST_PTS810 | SW5 |
| 1 | VGA Boot Sel | SW_SPST_PTS810 | SW6 |
| 1 | VGA RESET | SW_SPST_PTS810 | SW7 |
| 6 | TestPoint | Harwin-S1751-46-Test-Point | TP18, TP34, TP35, TP36, TP37, TP38 |
| 1 | ~{ROMEN_Amber} | LED_1206_3216Metric | D1 |
| 1 | SNDZ | LED_1206_3216Metric | D2 |
| 1 | DSK1 | LED_1206_3216Metric | D3 |
| 1 | -12v | LED_1206_3216Metric | D4 |
| 1 | +12v | LED_1206_3216Metric | D5 |
| 1 | Mega | LED_1206_3216Metric | D6 |
| 1 | 5V_2040_PWR | LED_1206_3216Metric | D7 |
| 1 | 3V3_PWR | LED_1206_3216Metric | D8 |
| 2 | 1SS389 | D_SOD-523 | D9, D26 |
| 1 | Stby | LED_1206_3216Metric | D10 |
| 1 | VID_Amber | LED_1206_3216Metric | D11 |
| 1 | AN0 | LED_1206_3216Metric | D12 |
| 1 | AN1 | LED_1206_3216Metric | D13 |
| 1 | AN2 | LED_1206_3216Metric | D14 |
| 1 | AN3 | LED_1206_3216Metric | D15 |
| 1 | DSK2 | LED_1206_3216Metric | D16 |
| 1 | BA15 | LED_1206_3216Metric | D17 |
| 1 | BA11 | LED_1206_3216Metric | D18 |
| 1 | BA14 | LED_1206_3216Metric | D19 |
| 1 | BA10 | LED_1206_3216Metric | D20 |
| 1 | BA13 | LED_1206_3216Metric | D21 |
| 1 | BA9 | LED_1206_3216Metric | D22 |
| 1 | BA12 | LED_1206_3216Metric | D23 |
| 1 | BA8 | LED_1206_3216Metric | D24 |
| 1 | -5V | LED_1206_3216Metric | D25 |
| 1 | KBD_Amber | LED_1206_3216Metric | D27 |
| 13 | 1uF | C_0805_2012Metric | C1, C2, C3, C7, C8, C9, C10, C11 +5 |
| 1 | 10uF | C_0805_2012Metric | C4 |
| 3 | T520A107M006ATE035 100u | CP_EIA-3216-18_Kemet-A | C5, C35, C62 |
| 10 | 1u | C_0805_2012Metric | C6, C30, C34, C37, C44, C51, C80, C81 +2 |
| 11 | 10u | C_0805_2012Metric | C12, C13, C14, C15, C17, C18, C19, C26 +3 |
| 13 | 100n | C_0603_1608Metric | C20, C21, C25, C28, C29, C31, C32, C33 +5 |
| 16 | 1u | C_0603_1608Metric | C22, C27, C36, C40, C41, C42, C43, C46 +8 |
| 4 | 27p | C_0603_1608Metric | C23, C24, C38, C39 |
| 4 | .1u | C_0805_2012Metric | C47, C52, C71, C72 |
| 4 | 100uF/20V | CP_EIA-3528-21_Kemet-B | C49, C69, C85, C86 |
| 4 | 22n | C_0805_2012Metric | C53, C70, C73, C74 |
| 3 | 1u | R_0805_2012Metric | C58, C60, C61 |
| 1 | 220n | R_1206_3216Metric | C59 |
| 4 | 47uF/25V | C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C87, C88, C89, C90 |
| 1 | 1e-6 | C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C91 |
| 2 | 4k7 | R_0603_1608Metric | R1, R79 |
| 2 | 3k3 | R_0603_1608Metric | R2, R3 |
| 28 | 4k7 | R_0805_2012Metric | R4, R5, R6, R7, R20, R24, R25, R26 +20 |
| 1 | 1 | R_0805_2012Metric | R8 |
| 1 | 2 | R_0805_2012Metric | R9 |
| 2 | 10k | R_0805_2012Metric | R10, R49 |
| 8 | 22 | R_0805_2012Metric | R11, R12, R13, R14, R15, R16, R17, R18 |
| 17 | 1k | R_0805_2012Metric | R19, R36, R59, R60, R68, R69, R74, R75 +9 |
| 2 | 0 | R_0603_1608Metric | R21, R33 |
| 4 | 27 | R_0603_1608Metric | R22, R23, R34, R35 |
| 2 | 1K | R_0603_1608Metric | R31, R73 |
| 1 | 470k | R_0805_2012Metric | R32 |
| 7 | 100 | R_0805_2012Metric | R37, R54, R55, R62, R63, R70, R71 |
| 3 | 1k | R_0402_1005Metric | R38, R41, R44 |
| 1 | 390 | R_0402_1005Metric | R39 |
| 2 | 2k2 | R_0402_1005Metric | R40, R43 |
| 2 | 470 | R_0402_1005Metric | R42, R45 |
| 2 | 470 | R_0603_1608Metric | R46, R56 |
| 1 | 470 | R_0805_2012Metric | R47 |
| 1 | 220 | R_0805_2012Metric | R48 |
| 1 | 150 | R_0805_2012Metric | R50 |
| 1 | 10k | R_0603_1608Metric | R84 |
| 2 | 100k | R_0603_1608Metric | R87, R88 |
| 3 | 100 | R_Array_Convex_4x0612 | RN1, RN2, RN3 |
Mega IIe design files
The KiCad project lives in the baldengineer/Mega-IIe repository on GitHub; these links point at the commit this page was built from.
Mega IIe: common questions
What microcontroller does the Mega IIe use?
The Mega IIe is built around the RP2040, from the RP2040/RP2350 family.
How big is the Mega IIe PCB?
The Mega IIe measures 163 × 174.4 mm, has 4 copper layers and is 4.69 mm thick.
How many components are on the Mega IIe?
307 components, from 125 distinct parts. The full bill of materials is listed on this page.
Where can I download the Mega IIe design files?
From the baldengineer/Mega-IIe repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Mega IIe design in my own project?
Yes, under the terms of its MIT license, which baldengineer chose for the repository.
Can I test firmware for the Mega IIe without the hardware?
Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug RP2040/RP2350 firmware against it before you order a PCB.
More boards in Mega-IIe
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Gd VGC proto
114.3 × 73.7 mm117 parts4LMIT33
RP2040/RP2350Servid rp2040-hdmi proto rev1
88.1 × 34.5 mm99 parts4LMIT33
RP2040/RP2350VGA Proto
37.1 × 63.8 mm62 parts2LMIT33
Gd IWM proto
93.2 × 54.7 mm60 parts2LMIT33
Gd MEGA-65c02 proto
98.8 × 100 mm56 parts4LMIT33
Gd MegaII proto
98.8 × 115.3 mm56 parts4LMIT33
IO Prototype (aka Slot)
94.8 × 64.6 mm37 parts2LMIT33
Gd 6502 proto
90.4 × 52.2 mm34 parts4LMIT33
Gd blackplane proto
155.5 × 93 mm33 parts2LMIT33
MegaII Breakout
91.4 × 91.4 mm21 parts2LMIT33
Earlier revisions in the repo: gd rev3
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