ORCA SBC/Interfaces and Connectors/UARTs
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| History | |||
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| Issue Date | Notes | ||
| First release | |||
| 2023/06/22 | Update J9 signals information | ||
Contents
UARTs interface[edit | edit source]
Description[edit | edit source]
The UARTs interfaces available on the Evaluation Kit are mapped to the following connectors:
- J8 is a 20x2x2.54mm pin header expansion connector that delivers many interfaces unused on board. On this connector are mapped these instances: UART1; UART2 (default debug console); UART4.
- J9 is a 8x1x1.25mm 53398-0871 Molex connector that delivers one RS232 4 wires (mapped to UART1) and one RS485 2 wires (mapped to UART3)
Signals[edit | edit source]
The following tables describe the interfaces signals:
J8[edit | edit source]
| Pin# | SOM Pin# | Pin name | Pin function | Pin Notes |
|---|---|---|---|---|
| 7 | J15.150 | SAI2_TXFS | UART1_CTS | shared with RS232 |
| 8 | J15.144 | SAI2_RXFS | UART1_TXD | shared with RS232 |
| 10 | J15.140 | SAI2_RXC | UART1_RXD | shared with RS232 |
| 11 | J15.142 | SAI2_RXD0 | UART1_RTS | shared with RS232 |
| 19 | J15.122 | ECSPI2_MOSI | UART4_TXD | Transmit signal (OUT) |
| 21 | J15.120 | ECSPI2_MISO | UART4_CTS | Clear to send (OUT) |
| 23 | J15.124 | ECSPI2_SCLK | UART4_RXD | Receive signal (IN) |
| 24 | J15.126 | ECSPI2_SS0 | UART4_RTS | Request to send (IN) |
| 27 | J15.248 | UART2_RXD | UART2_RXD | default debug console |
| 29 | J15.250 | UART2_TXD | UART2_TXD | default debug console |
| 31 | J15.256 | UART4_RXD | UART4_RXD | alternative to ECSPI2_SCLK |
| 33 | J15.258 | UART4_TXD | UART4_TXD | alternative to ECSPI2_MOSI |
| 1, 17 | - | 3V3_CB | Power output for transceiver supply | BOARD_PGOOD driven rail |
| 6, 9, 14, 20, 25, 30, 34, 39 | - | DGND | Ground |
J9[edit | edit source]
| Pin# | SOM Pin# | Pin name | Pin function | Pin Notes |
|---|---|---|---|---|
| 1 | - | RS485_A | Non inverting BUS signal | UART3 |
| 2 | - | RS485_B | Inverting BUS signal | UART3 |
| 3 | - | RS485_B_120R | Termination resistor | connect this signal to RS485_B
to enable the 120R termination |
| 4 | - | DGND | Ground | |
| 5 | J15.144 | RS232_TX | Transmit line | UART1_TXD (shared with J8.8) |
| 6 | J15.140 | RS232_RX | Receive line | UART1_RXD (shared with J8.10) |
| 7 | J15.150 | RS232_CTS | Clear to send line | UART1_CTS (shared with J8.7) |
| 8 | J15.142 | RS232_RTS | Request to send line | UART1_RTS (shared with J8.11) |
Device mapping[edit | edit source]
UART1 is mapped to /dev/ttymxc0 device in Linux
UART2 is mapped to /dev/ttymxc1 device in Linux. The peripheral is used as the default serial console, both for the bootloader and the kernel.
UART3 is mapped to /dev/ttymxc2 device in Linux
UART4 is mapped to /dev/ttymxc3 device in Linux
Device usage[edit | edit source]
The TTL UARTs on J8 can be connected to external devices that use 0-3.3V levels.
The RS232 and RS485 uses the standard protocols.
