esp32 hosted

Handshake pin

ESP Of Output Pin . A high level indicates that... Is in progress ESP32 Passing spi Interface interacts with the host . therefore , When the pin is high , The host should not start spi The data transfer . The popular explanation is ：host Want to give ESP32 send data , Have a look first esp32 Are you ready to receive data .

Data ready pin

ESP Of Output Pin . because ESP yes spi The slave device of , The transmission cannot be initiated . therefore , This pin is used to compensate SPI The inadequacy of the agreement , tell SPI host ,esp32 You want to send data to the host . This pin remains high , Until the host reads the packet .

Reset/EN pin

ESP Peripheral Input Pin . Used to reset ESP equipment .

esp32 The code internally maintains a spi Of rx_buffer and tx_buffer. Every buffer The biggest problem is 1600 byte , That is, the host can send and receive at most 1600 Bytes of data .

stay esp32 and host When exchanging data , Use protobuf Serialize and deserialize data .

If you want to add a new command interaction ：

1、 stay .proto Add custom commands in the file , Then generate .c and .h file ：

cd <path/to/esp_hosted>/common/proto

protoc-c esp_hosted_config.proto --c_out=.

mv esp_hosted_config.pb-c.c ../

mv esp_hosted_config.pb-c.h ../include/

2、 stay host/host_common/commands.c Add C function

3、 stay ESP End , stay esp/esp_driver/network_adapter/main/slave_commands.c Add the corresponding C Function to handle the added message fields .

When host to esp32 When sending a command , First use protobuf Serialize the command , And then call transport_pserial_data_handler Interfaces assemble data into TLV Format (Type - Length - Value),

Field	explain	bytes used
Endpoint Type	1： Indicates that the next transmission is endpoint name	1 byte
Endpoint Length	Indicates the next transmitted Endpoint Value Size	2 byte
Endpoint Value	There is only one value, Fixed is ："control"	7 byte
Data Type	2： Indicates that the next transmission is the data content	1 byte
Data Length	Indicates the next transmitted Data Value Size	2 byte
Data Value	payload	N bytes