1. provide options for bluetooth low power mode
2. provide two options for bluetooth low power clock: main XTAL and external 32kHz XTAL
3. provide function and callbacks to control bluetooth low power mode, including enable/disable sleep, software wakeup request, low power clock settings, check power state, etc
4. modify vhci API vhci_host_send_packet to use blocking mode
5. note that DFS and bluetooth modem sleep can not be used together currently.
1. move settings of WIFI_CLK_EN_REG for bluetooth into controller init/deinit APIs
2. modify the bit mask used in phy_rf init/deinit to use WIFI-BT shared bits
1. When dual core cpu run access DPORT register, must do protection.
2. If access DPORT register, must use DPORT_REG_READ/DPORT_REG_WRITE and DPORT_XXX register operation macro.
1. configure LEDC timer saparately
2. add peripher_crtl.c/.h
To enable the peripheral modules, we have to set/clear the control register in dport_reg.h.
These bits are disabled by default and they are all in a same register, so we need to add a lock on that.
3. add include esp_err.h in gpio.h
