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# Board layout and jumper settings The following figure shows the top view of QCC743M, QCC744M and QCC748M boards. **Figure: Top view of QCC743M, QCC744M, and QCC748M boards** The following table summarize the jumper settings used to configure GPIO routing, JTAG and UART signals, and I/O voltage options on the board. Jumper configuration (QCC743M EVK 4.1 and QCC744M/QCC748M EVK 3.1) | Jumper | Pin 1 | Pin 2 | Description | | --- | --- | --- | --- | | J3 | 1 | 2 | GPIO2 connected to CH347-DTR1 | | J3 | 3 | 4 | GPIO2 connected to CH347-TDO (JTAG) | | J3 | 5 | 6 | GPIO1 connected to CH347-TCK (JTAG) | | J3 | 7 | 8 | GPIO3 connected to CH347-TDI (JTAG) | | J3 | 9 | 10 | GPIO0 connected to CH347-TMS (JTAG) | | J3 | 11 | 12 | GPIO22 connected to CH347-TXD1 (UART) | | J3 | 13 | 14 | GPIO21 connected to CH347-RXD1 (UART) | | J3 | 15 | 16 | GPIO28 connected to CH347-CTS1 (UART) | | J3 | 17 | 18 | GPIO29 connected to CH347-RTS1 (UART) | | J4 | 1 | 2 | 3.3 V connected to chip VDD33 | | J4 | 3 | 5 | VDDIO2 set to 3.3 V | | J4 | 5 | 7 | VDDIO2 set to 1.8 V | | J4 | 4 | 6 | VDDIO1 set to 3.3 V | | J4 | 6 | 8 | VDDIO1 set to 1.8 V | | J4 | 9 | 11 | GPIO30 connected to CHIP\_EN (RESET button - S2) | | J4 | 11 | 13 | CHIP\_EN connected to CH347-RTS1 | | J4 | 10 | 12 | CH347F VIO set to 1.8 V | | J4 | 12 | 14 | CH347F VIO set to 3.3 V | | J4 | 15 | 16 | USB host feature not supported (QCC743M/QCC744M); Connect to enable USB host feature (QCC748M) | | J4 | 17 | 18 | USB supply connected to LDO/BUCK | The default configuration has the jumper connected to 3.3 V for I/O supply during current measurement. To use the 1.8 V I/O supply for current measurement, configure the jumper settings as follows: - J4: connect pins 5 and 7 together. - J4: connect pins 6 and 8 together. Last Published: May 06, 2026 Previous Topic Module feature comparison Next Topic LEDs and buttons