Author: ShifangZ_26 Version: **
Question:
How can I enable cable discovery in the CCGx Power SDK Firmware?
Answer:
Cable discovery needs VCONN support as a prerequisite. Follow these steps to enable VCONN support:
1. Add VCONN circuits into CCGx design.
- 3.3 V-5.0 V (@650-mA minimum) power source should be supplied for VCONN source.
- VCONN_CTRL_CCx should be wired to unused GPIOs.
P MOS FETs on VCONN circuits should be of small capacities (both On or Off states) (<600 pF) and Continuous Drain Current (>1 W at 3.3 V).
2. Enable cable discovery with EZ-PD configuration and update config.c in the firmware project.
3. Add VCONN control functions into the project and register them into Application callback functions for the DPM.
a. Add two pins named VCONN_CC1 and VCONN_CC2 into TopDesign.cysch for VCONN support.
b. VCONN control functions are as follows:
#define VCONN_SUPPORT_ENABLE (1)
#if VCONN_SUPPORT_ENABLE
#define VCONN_SWITCH_ON_VALUE (0)
#define VCONN_SWITCH_OFF_VALUE (1)
void pb_vconn_enable(uint8_t port, uint8_t channel)
{
if (channel == CC_CHANNEL_1)
{
VCONN_CC1_Write(VCONN_SWITCH_ON_VALUE);
}
else
{
VCONN_CC2_Write(VCONN_SWITCH_ON_VALUE);
}
/* Reset RX Protocol for cable */
dpm_prot_reset_rx(port, SOP_PRIME);
dpm_prot_reset_rx(port, SOP_DPRIME);
}
void pb_vconn_disable(uint8_t port, uint8_t channel)
{
if (channel == CC_CHANNEL_1)
{
VCONN_CC1_Write(VCONN_SWITCH_OFF_VALUE);
}
else
{
VCONN_CC2_Write(VCONN_SWITCH_OFF_VALUE);
}
}
bool pb_vconn_is_present(uint8_t port)
{
bool state;
if (dpm_get_info(port)->rev_pol == 0)
{
state = VCONN_CC1_Read();
}
else
{
state = VCONN_CC2_Read();
}
if (state == VCONN_SWITCH_ON_VALUE)
{
return true;
}
return false;
}
#endif /* VCONN_SUPPORT_ENABLE */
c. Register the updated functions into Application callback functions for the DPM.
