This is a HAT (extension board) for Raspberry Pi containing 4 serial port chips and a power input with a DC/DC converter. Each of the serial ports has 3.3V logic levels, appropriate converters are needed for RS232 or RS485 signal levels.
Schema, production files in the format needed for Seeed Studio.
Plug the device onto a Raspberry Pi and hope that someone wrote a driver for it ;)
| 1 | GND | Power ground. |
| 2 | GND | Power ground. |
| 3 | +5V | Power supply +5V. |
| 4 | +5V | Power supply +5V. |
| 5 | +3.3V | Power supply +3.3V. |
| 6 | +3.3V | Power supply +3.3V. |
| 7 | TXD | TXD, 3.3V logic level. |
| 8 | RXD | RXD, 3.3V logic level. |
| 9 | RTS | RTS, for DE of RS485 driver, 3.3V logic level. |
| 10 | RS485 | RS485 flag input, 3.3V=RS485, 0V=RS232. |
TODO: Describe the RPi signals used.
Power supply voltage depending on the DC/DC converter. When using Traco TEN 5-4811WI a voltage between 18 and 75 VDC can be supplied.
| 1 | VIn- | Negative power supply pin. |
| 2 | VIn+ | Positive power supply pin. |
The extension connector can be used to connect up to 8 additional SPI devices.
| 1 | GND | Power ground. |
| 2 | GND | Power ground. |
| 3 | +5V | Power supply +5V. |
| 4 | +5V | Power supply +5V. |
| 5 | +3.3V | Power supply +3.3V. |
| 6 | +3.3V | Power supply +3.3V. |
| 7 | CS5-8 | Chip select 5-8. |
| 8 | MISO | MISO from RPi. |
| 9 | MOSI | MOSI from RPi. |
| 10 | CS9-12 | Chip select 9-12. |
| 11 | CTL0 | Control bit 0. |
| 12 | CTL1 | Control bit 1. |
| 13 | RESET | Reset signal generated on the HAT. |
| 14 | SCK | SCK from RPi. |
| Ref. | Count | Description |
|---|---|---|
| - | 1 | Borg RPi Quad Serial HAT PCB |
| C1,C2,C3,C4,C5,C6,C7,C8,C11,C12,C21,C31,C41 | x | Capacitor 100n 0805 |
| C9,C10 | 2 | Capacitor 22p 0805 |
| D1 | 1 | SS14 SMD/SMB |
| D2 | 1 | 1N4007 SMD/SMA |
| J1 | 1 | Jumper |
| P1,P2,P3,P4 | 4 | 10 pin IDC |
| P5 | 1 | 40 pin ??? |
| P6 | 1 | Screw terminal, 3 pin, 5mm. |
| P7 | 1 | Pin header, 14 pin. |
| R1 | 1 | Resistor 100k, 0805 |
| R2,R5 | 2 | Resistor 1k, 0805 |
| R3,R4 | 2 | Resistor 3.9k, 0805 |
| U1 | 1 | 74165, TSSOP14 |
| U2 | 1 | 74595, TSSOP16 |
| U3 | 1 | 74125_1G |
| U4 | 1 | 7404, TSSOP14 |
| U5 | 1 | 7410, TSSOP14 |
| U6 | 1 | 74139, TSSOP16 |
| U7 | 1 | SN74LVC1404, TSSOP8 |
| U8 | 1 | DCDC |
| U9 | 1 | CAT24C32, TSSOP8 |
| U10 | 1 | 3.3V Voltage Regulator |
| U11,U21,U31,U41 | 4 | SC16IS740IPW |
| X1 | 1 | Crystal 7.3728MHz, HC49S |
