SAP-Plus Memory Loader

TomNisbet·sap-plus·schematics/memory-loader/memory-loader.kicad_pcb

About the SAP-Plus Memory Loader PCB

SAP-Plus Memory Loader is an open source PCB design by TomNisbet, published on GitHub under the MIT license. It is a 2-layer board measuring 150 × 100 mm, with 57 components from 41 distinct parts.

Other key parts include the 74LS00, 74LS245, 74LS74, 74LS193 and NE555P. By type, the board carries 14 switches, 12 resistors, 11 diodes, 10 capacitors, 8 ICs and 2 connectors.

From the project

Simple As Possible (SAP) 8-bit computer with a modular PCB design

Add RAM READ/WRITE switch to allow read back of RAM values by holding the flip-flop in reset and writing only to the MAR RST signal no longer resets the state flip-flow * Clean up silkscreen labels with new text and positioning

Switch clock phase on state flip-flop and LAR counter - state now uses inverted CLK to change on falling edge and LAR uses CLK LAR now increments in WRAM state instead of WMAR state - this means that the LAR LEDs will show the current MAR address while the user is setting the switches for the RAM value New footprint for rocker switches SW1..SW8 with larger holes…

Main components on the SAP-Plus Memory Loader

74LS00 74LS245 74LS74 74LS193 NE555P 74LS10

SAP-Plus Memory Loader bill of materials (BOM)

57 components, 41 distinct parts.

Qty	Part	Footprint	Refs
1	74LS00	DIP-14_W7.62mm	U1
2	74LS245	DIP-20_W7.62mm	U2, U3
1	74LS74	DIP-14_W7.62mm	U4
2	74LS193	DIP-16_W7.62mm	U5, U6
1	NE555P	DIP-8_W7.62mm	U7
1	74LS10	DIP-14_W7.62mm	U8
1	Conn_02x10_Odd_Even	PinHeader_2x10_P2.54mm_Vertical	J1
1	5V POWER	TerminalBlock_RND_205-00012_1x02_P5.00mm_Horizontal	J2
1	SD0	RockerSwitch CIT RA-14xxxxC	SW1
1	SD1	RockerSwitch CIT RA-14xxxxC	SW2
1	SD2	RockerSwitch CIT RA-14xxxxC	SW3
1	SD3	RockerSwitch CIT RA-14xxxxC	SW4
1	SD4	RockerSwitch CIT RA-14xxxxC	SW5
1	SD5	RockerSwitch CIT RA-14xxxxC	SW6
1	SD6	RockerSwitch CIT RA-14xxxxC	SW7
1	SD7	RockerSwitch CIT RA-14xxxxC	SW8
1	RESET	SW_PUSH-12mm_Wuerth-430476085716	SW9
3	SW_SPDT	SW_EG1218	SW10, SW13, SW14
1	SET	SW_PUSH-12mm_Wuerth-430476085716	SW11
1	CLOCK	SW_PUSH-12mm	SW12

Show 21 more

Qty	Part	Footprint	Refs
1	A0	LED_D3.0mm	D1
1	A1	LED_D3.0mm	D2
1	A2	LED_D3.0mm	D3
1	A3	LED_D3.0mm	D4
1	A4	LED_D3.0mm	D5
1	A5	LED_D3.0mm	D6
1	A6	LED_D3.0mm	D7
1	A7	LED_D3.0mm	D8
1	MAR	LED_D3.0mm	D9
1	RAM	LED_D3.0mm	D10
1	ACTIVE	LED_D3.0mm	D11
9	0.1uF	C_Disc_D3.0mm_W1.6mm_P2.50mm	C1, C2, C3, C4, C5, C6, C7, C8 +1
1	0.01uF	C_Disc_D3.0mm_W1.6mm_P2.50mm	C9
5	10K	R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal	R1, R2, R3, R9, R10
1	1K	R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal	R4
1	1M	R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal	R5
1	R-GRN	R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal	R6
1	R-RED	R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal	R7
1	R-WHT	R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal	R8
1	4.7K	R_Array_SIP9	RN1
1	10K	R_Array_SIP9	RN2

SAP-Plus Memory Loader design files

The KiCad project lives in the TomNisbet/sap-plus repository on GitHub; these links point at the commit this page was built from.

SAP-Plus Memory Loader: common questions

How big is the SAP-Plus Memory Loader PCB?

The SAP-Plus Memory Loader measures 150 × 100 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the SAP-Plus Memory Loader?

57 components, from 41 distinct parts. The full bill of materials is listed on this page.

Where can I download the SAP-Plus Memory Loader design files?

From the TomNisbet/sap-plus repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the SAP-Plus Memory Loader design in my own project?

Yes, under the terms of its MIT license, which TomNisbet chose for the repository.

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