2 layers
2 layers100 × 85 mm
B68k io
Lougous/b68k-ioIO extension board for b68k computer
- Size
- 100 × 85 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 66
- Nets
- 93
- Pads
- 315
- Tracks, vias
- 865, 75
- Pours
- 5
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 4 Jun 2024
- Updated
- 11 Jun 2024
Overview
B68k io is an open-source printed circuit board by Lougous, from the Lougous/b68k-io repository on GitHub, published under the MIT licence. It is a 2-layer board of 100 × 85 mm with 66 parts on 93 nets, routed with 865 tracks and 75 vias.
It is built around the 74LVC244, MAX232N and DS1307+. Its parts include 24 resistors, 14 capacitors, 12 connectors, 7 ICs and 2 fuses. It belongs with the PIC boards of this library.
Main components
3
74LVC244
TSSOP-20Buffers, Drivers, Receivers, TransceiversWuxi I-core Elec
MAX232N
PDIP-160℃~+70℃ 120Kbps 2 2 4.5V~5.5V Transceiver PDIP-16 RS232 ICs ROHSTexas InstrumentsRS232 ICs
DS1307+
DIP-80℃~+70℃ 300nA 4.5V~5.5V Backup power management and battery charging、InsideSRAM/NVRAM、Programmable clock output External I2C DIP-8 Real Time Clocks ROHSMaxim Integrated (Analog Devices)Real Time Clocks
README
README.mdb68k-io
IO extension board for b68k computer.
Features
- local bus peripheral to b68k-cpu computer
- a UART with DB9 connector (RS232, no hardware flow control)
- an I2C bus with onboard RTC chip (DS1307+) with crystal and backup battery, and 4-pins pin header extension connector
- a SPI bus with 7 chip select lines: 2x SD cards slots, 1x through an 8-pins pin header extension connector, 4x through DB15 connector for external equipements (external SPI slaves are electrically isolated from internal slaves)
Board fonctions are implemented with a PIC18F27K42 microcontroller.
The board has only two memory locations accessible through the expansion bus: one to set the actual register to access, the other to read or write data from/to the register.
| register | address | description |
|---|---|---|
| DATA | XX0000h | register data |
| ADDRESS | XX0001h | register index |
Register set
| register | index | description |
|---|---|---|
| SPI_SEL | 0 | [5..3] : enabled SPI chip select line 0: external #0 1: external #1 2: external #2 3: external #3 4: SD card A 5: SD card B 6: internal pin header 7: none (reset) |
| SPI_CTRL | 1 | bit 7: BUSY r bit 2: CLRBF s bit 1: TXR rw bit 0: RXR rw |
| SPI_DATA | 2 | SPI data in/out |
| UART_STS | 4 | UART status bit 7: TX ready bit 1: RX FIFO overflow bit 0: RX FIFO underflow |
| UART_DATA | 5 | UART data in/out |
| I2C_CTRL | 6 | bit 7: RXIF bit 5: TXBE bit 2: reset bit 1: start bit 0: RXBF |
| I2C_CNT | 7 | |
| I2C_DATA | 8 | |
| I2C_CMD | 9 | bit 7..1: address bit 0: RWn |
| IRQCFG | 14 | interrupt controller configuration bit 0: enable UART RX interrupt |
| IRQSTS | 15 | interrupt controller status bit 0: UART RX interrupt pending |
Parts
66| Qty | Value | Footprint | References |
|---|---|---|---|
| 18 | 10k | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R1, R2, R3, R4, R5, R6, R7, R12, R13, R15, R16, R20, R21, R22, R23, R24 +2 |
| 6 | 100n | Capacitor_THT:C_Disc_D4.3mm_W1.9mm_P5.00mm | C1, C3, C4, C5, C8, C10 |
| 5 | 1k | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R10, R11, R17, R18, R19 |
| 4 | C | Capacitor_THT:C_Disc_D4.3mm_W1.9mm_P5.00mm | C9, C11, C12, C16 |
| 4 | MountingHole | MountingHole:MountingHole_2.7mm_M2.5_DIN965_Pad | H5, H6, H7, H8 |
| 2 | 100u | Capacitor_THT:CP_Radial_D5.0mm_P2.00mm | C6, C7 |
| 2 | 74LVC244 | Package_DIP:DIP-20_W7.62mm_Socket | U4, U6 |
| 2 | Conn_01x06 | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Horizontal | J4, J8 |
| 2 | Fuse | Resistor_THT:R_Axial_DIN0411_L9.9mm_D3.6mm_P5.08mm_Vertical | F1, F2 |
| 2 | SD_Card | Connector_Card:SD_Kyocera_145638009511859+ | J2, J7 |
| 1 | 10n | Capacitor_THT:C_Disc_D4.3mm_W1.9mm_P5.00mm | C2 |
| 1 | 10u | Capacitor_THT:C_Disc_D4.3mm_W1.9mm_P5.00mm | C14 |
| 1 | 500 | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R14 |
| 1 | 74LS138 | Package_DIP:DIP-16_W7.62mm_Socket | U3 |
| 1 | Battery_Cell | cr2032:CR2032H | BT1 |
| 1 | Conn_01x02 | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J5 |
| 1 | Conn_01x03 | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J12 |
| 1 | Conn_01x04 | Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Horizontal | J6 |
| 1 | Conn_01x06 | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical | J10 |
| 1 | Conn_01x08 | Connector_PinHeader_2.54mm:PinHeader_1x08_P2.54mm_Vertical | J11 |
| 1 | Conn_02x10_Odd_Even | Connector_PinSocket_2.54mm:PinSocket_2x10_P2.54mm_Vertical | J1 |
| 1 | Crystal | Crystal:Crystal_C38-LF_D3.0mm_L8.0mm_Horizontal | Y1 |
| 1 | DB15_Male_MountingHoles | Connector_Dsub:DSUB-15_Male_Horizontal_P2.77x2.84mm_EdgePinOffset7.70mm_Housed_MountingHolesOffset9.12mm | J3 |
| 1 | DB9_Male_MountingHoles | Connector_Dsub:DSUB-9_Male_Horizontal_P2.77x2.84mm_EdgePinOffset9.90mm_Housed_MountingHolesOffset11.32mm | J9 |
| 1 | DS1307+ | Package_DIP:DIP-8_W7.62mm_Socket | U1 |
| 1 | LD1086D2T33TR | Package_TO_SOT_THT:TO-220-3_Horizontal_TabDown | U5 |
| 1 | LED | LED_THT:LED_D3.0mm | D1 |
| 1 | MAX232 | Package_DIP:DIP-16_W7.62mm_Socket | U7 |
| 1 | PIC18F24K22-xSP-MCU_Microchip_PIC18 | Package_DIP:DIP-28_W7.62mm_Socket | U2 |
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Questions
How big is the B68k io PCB?
It measures 100 × 85 mm and has 2 copper layers, 1.6 mm thick.
What parts does the B68k io use?
66 parts, built around the 74LVC244, MAX232N and DS1307+. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the B68k io KiCad files?
From the Lougous/b68k-io repository on GitHub, at the commit this page was made from: the board is board/io.kicad_pcb and its schematic board/io.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the B68k io design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).