esp-idf/examples/peripherals/spi_slave_hd/segment_mode

SPI Slave Halfduplex: Segment Mode Examples

(See the README.md file in the 'examples' directory for more information about IDF examples.)

These two projects illustrate the SPI Slave Halfduplex Segment Mode.

• seg_slave shows one of the ways to use the SPI Slave Halfduplex driver. There are 2 tasks repeating to receive/send transactions from/to SPI Master respectively.
• seg_master shows how to use the ESP Serial Slave Link APIs to communicate with SPI Slave Halfduplex driver. It receives/sends transactions from/to slave a few times.

How to use example

Hardware Required

These two projects are supposed to be flashed onto two seperate boards and jumped together via correctly connected SPI pins defined in both of the app_main.c files. For the seg_master project, it could be flashed onto all the ESP Chips. Whereas the seg_slave currently could be flashed onto ESP32-S2. Once they are connected and flashed, they will use the SPI Master and SPI Slave Halfduplex drivers to communicate with each other.

Following is the connection between 2 ESP32S2 boards:

Signal	Master	Slave
MOSI	GPIO11	GPIO11
MISO	GPIO13	GPIO13
SCLK	GPIO12	GPIO12
CS	GPIO10	GPIO10

(Feel free to change the GPIO settings by editing the macro definations at the top of app_main.c files.)

Build and Flash

Run idf.py -p PORT flash monitor to build, flash and monitor the project.

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for full steps to build, flash and monitor projects.

Example Output

seg_master

---------SLAVE INFO---------

Slave MAX Send Buffer Size:       5000
Slave MAX Receive Buffer Size:    120
I (328) SEG_MASTER: RECEIVING......
Transaction No.0 from slave, length: 4640
I (338) SEG_MASTER: SENDING......
I (348) SEG_MASTER: RECEIVING......
Transaction No.1 from slave, length: 3299
I (348) SEG_MASTER: SENDING......
I (358) SEG_MASTER: RECEIVING......
Transaction No.2 from slave, length: 4836
I (368) SEG_MASTER: SENDING......
I (368) SEG_MASTER: RECEIVING......
Transaction No.3 from slave, length: 3333
I (378) SEG_MASTER: SENDING......
I (378) SEG_MASTER: RECEIVING......
Transaction No.4 from slave, length: 4965
I (388) SEG_MASTER: SENDING......
I (388) SEG_MASTER: RECEIVING......
Transaction No.5 from slave, length: 3042
I (398) SEG_MASTER: SENDING......
I (408) SEG_MASTER: RECEIVING......
Transaction No.6 from slave, length: 4892
I (408) SEG_MASTER: SENDING......
I (418) SEG_MASTER: RECEIVING......
Transaction No.7 from slave, length: 3585
I (428) SEG_MASTER: SENDING......
I (428) SEG_MASTER: RECEIVING......
Transaction No.8 from slave, length: 3348
I (438) SEG_MASTER: SENDING......
I (438) SEG_MASTER: RECEIVING......
Transaction No.9 from slave, length: 4985
I (448) SEG_MASTER: SENDING......
I (448) SEG_MASTER: RECEIVING......
Transaction No.10 from slave, length: 3710
...

seg_slave

77 bytes are received:
this is master's transaction 0
109 bytes are received:
this is master's transaction 1
83 bytes are received:
this is master's transaction 2
97 bytes are received:
this is master's transaction 3
47 bytes are received:
this is master's transaction 4
89 bytes are received:
this is master's transaction 5
80 bytes are received:
this is master's transaction 6
96 bytes are received:
this is master's transaction 7
83 bytes are received:
this is master's transaction 8
110 bytes are received:
this is master's transaction 9
113 bytes are received:
this is master's transaction 10
...

Troubleshooting

For any technical queries, please open an issue on GitHub. We will get back to you.