The following signals are necessary for RX direct mode
RX data clock output
RX data output
You can assign them to any radio GPIO pin by setting the corresponding GPIO_MODE to RX_DATA_CLK or RX_DATA via the GPIO_PIN_CFG command.
The following signals are necessary for TX direct mode
TX data clock output
You can assign it to any radio GPIO pin by setting the corresponding GPIO_MODE to TX_DATA_CLK via the GPIO_PIN_CFG command.
TX data input
The TX_DIRECT_MODE_GPIO field of the MODEM_MOD_TYPE property determines which radio GPIO pin is selected as the modulation data source during TX Direct mode. Also the GPIO_MODE of the corresponding radio GPIO has to be set to INPUT via the GPIO_PIN_CFG command.
When generating the configuration from WDS, GPIO mode can be selected on the "GPIO and FRR" tab of the configurator. However the TX_DIRECT_MODE_GPIO field is left by WDS always in the default GPIO0 setting and can be modified only by hand in the generated config header.
Note 1: For Si4x55 the TX data input can be assigned only to GPIO0.
Note 2: For active signals like data and clock, the GPIO0 and GPIO1 pins should be primarily used , because these have less susceptibility to generating spurious components in the synthesizer than GPIO2 and GPIO3 have.
Proprietary Knowledge Base
Direct mode GPIO configuration on Si4x6x and Si4x55
The following signals are necessary for RX direct mode
RX data clock output
RX data output
You can assign them to any radio GPIO pin by setting the corresponding GPIO_MODE to RX_DATA_CLK or RX_DATA via the GPIO_PIN_CFG command.
The following signals are necessary for TX direct mode
TX data clock output
You can assign it to any radio GPIO pin by setting the corresponding GPIO_MODE to TX_DATA_CLK via the GPIO_PIN_CFG command.
TX data input
The TX_DIRECT_MODE_GPIO field of the MODEM_MOD_TYPE property determines which radio GPIO pin is selected as the modulation data source during TX Direct mode. Also the GPIO_MODE of the corresponding radio GPIO has to be set to INPUT via the GPIO_PIN_CFG command.
When generating the configuration from WDS, GPIO mode can be selected on the "GPIO and FRR" tab of the configurator. However the TX_DIRECT_MODE_GPIO field is left by WDS always in the default GPIO0 setting and can be modified only by hand in the generated config header.
Note 1: For Si4x55 the TX data input can be assigned only to GPIO0.
Note 2: For active signals like data and clock, the GPIO0 and GPIO1 pins should be primarily used , because these have less susceptibility to generating spurious components in the synthesizer than GPIO2 and GPIO3 have.