RTLPlayground/doc/devices/SWTG024AS.md

SWTG024AS

SWTG024AS has at least 4 variants that look the same.

Variants are managed and a unmanaged version. But both have pcb version v1.0 and v2.0. Also the RJ45 connects can be all plastic or metal shielding.

Unmanaged Switch

Brands

Brand	Type	Managed	PCB	PCB Label	Flash	Chip RTL
LIANGUO	SWTG024AS	No	SWTG024AS-v2.0	CM-23-11-2336 023-17453	512kB	8272

SWTG024AS-v2.0 managed vs unmanged

Changed I found with my own board vs Managed version of the PCB.

Bottom

• R105: Installed, goes to R10-PullDown SFP2 -> TX DISABLE
• R85: Not Installed (Connected to K1)
• R90: Not installed (PowerLed)
• LED3: Not installed (PowerLed)

Top

• K1: Not installed (Reset butten)
• R95: Installed (SFP2 signal RX-LOS), mean that the manage version can use RX-LOS function.
• R270: Installed (SFP1 signal RX-LOS)
• R268: Installed (SFP2 signal TX_DISABLE, but R262 200R pull-down is to high to drive by the SOC, needs mod!)

Notes

• TX Disable-SFP2 and Button K1 share the same GPIO pin via R105 and R85. But with R88, TX Disable-SFP2 can be mapped to C4.
• TX Disable pull-down resistos on both SFP are to low to drive by the SOC. We need to make a Best-BOM variant so we can use all the featues.

Connectors

J4 SFP1 PINs	Signal	Component	GPIO	Notes
2	TX_FAULT	B-R262	---
3	TX_DISABLE	B-R263, T-R268	C6	R262 = Pull-down 200R
4	MODDEF2 – SDA	B-R261	C7
5	MODDEF1 – SCL	B-R260, T-R267	---
6	MODDEF0 – PRESENT	B-R259, T-R296	B30
7	RATE SEL	B-R257	---
8	LOS	B-R258, T-R270	C5
9	TO?	B-R256	---

J2 SFP2 PINs	Signal	Component	GPIO	Notes
2	TX_FAULT	B-R70	---
3	TX_DISABLE	B-R10, T-R88-L	C22	R10 = Pull-down 200R
4	MODDEF2 – SDA	B-R26	C9
5	MODDEF1 – SCL	B-R15, T-R87	---
6	MODDEF0 – PRESENT	B-R14, T-R89	C18
7	RATE SEL	B-R12	---
8	LOS	B-R13, T-R95	C19
9	TO?	B-R11	---

Note: component numbering <L>-<REFDES>-<SIDE>

• L: Layer, T=Top, B=Bottom
• REFDEES: full silkscreen like R123
• SIDE: Side of the component. when the rj45 are facing towards you are you can read the silkscreen normal. L = Left, R=right, B=bottom, T=top or P with a pin number.

T3

This connector seems to go to U4 and U10. I thing is used to connect a external CPU to controlle the SOC. Even to program the flash via the SOC. Signals are based on that U4 is likely a I2C-EEPROM, U10 is likely other SPI-chip.

T3 pin	what	Signal
1	U4-P6, 33R U10-P6	I2C-SCL, SPI-CLK
2	GND	---
3	U4-P5, U10-P5	I2C-SDA, SPI-DI/DO
4	VCC
5	33R -> U10-P2	SPI-DO/D1
6	U10-P1	SPI-CS

T8 pin	what	Signal
1	C14
2	GND
3	C16
4	3V3
5	C15
6	C17

Reset ciruit

Cmp	Function
R78	33k PullUp
D3	Discharge Diode
C187	RC-Delay

Reset-line found at T-D3-D active-low.