I2C

1 Function Overview

The I2C interface can be connected to the I2C or SMBus bus through the data pin (SDA) and clock pin (SCL). Both SDA and SCL lines are set as open-drain outputs and are connected to pull-up resistors. Therefore, multiple devices can be mounted on the I2C and SMBus buses. Each I2C interface transmission is initiated and controlled by the master device
This chapter mainly introduces the completion of data read and write operations on the EEPROM chip through the I2C interface. Currently, the CP side does not allow the use of I2C, while the AP side supports the use of I2C0 and I2C1.
For theoretical introduction to I2C, refer to: I2C_driver

Note

1.The CP side does not allow the use of I2C0 and I2C1;
2.The AP side supports the use of I2C0 and I2C1;

2 code path

demo_path：

components\bk_cli\cli_i2c.c

driver_source_code_path：

ap\middleware\driver\i2c\i2c_driver.c

ap\middleware\driver\i2c\sim_i2c_driver_v2.c

Note

1.i2c_driver.c :Hardware interrupt implementation code
- 2.sim_i2c_driver_v2.c:Pure software implementation code

3 cli Command Overview

Demo Running Dependencies: Macro Configuration

NAME

Description

File

value

CONFIG_I2C

support i2c

ap\middleware\soc\bk7236\bk7236.defconfig

y

CONFIG_I2C_SUPPORT_ID_BITS

support i2c0 or i2c1

ap\middleware\soc\bk7236\bk7236.defconfig

1

CONFIG_SIM_I2C

value y:support software； n: hardware i2c

ap\middleware\soc\bk7236\bk7236.defconfig

n

CONFIG_SIM_I2C_HW_BOARD_V3

support Touch Screen with i2c

ap\middleware\soc\bk7236\bk7236.defconfig

y

The demo supports the following commands:

Command

Param

Description

i2c_driver init

none

init I2C driver control memory

i2c_driver deinit

none

free all resource related to I2C

i2c {id} init

i2c id number

power up and start the I2C id

i2c {id} deinit

i2c id number

power down and Stop the I2C id

i2c {id} memory_write {data_size} {dev_addr} {mem_addr_size}

id: i2c id number

write data_size bytes of data to the slave device with address dev_id

data_size:size of data written

dev_addr: slave device address

mem_addr_size: size of memory_addr

i2c {id} memory_read {data_size} {dev_addr} {mem_addr_size}

id: i2c id

read data_size bytes of data from slave device

data_size:size of data read

dev_addr: slave device address

mem_addr_size: size of memory_addr

4 I2C PIN Descriptions

I2C0 corresponds to 1 set of PIN, the corresponding hardware pins are as follows:

I2C0 function

group0

I2C0_CLK

GPIO0

I2C0_SDA

GPIO1

I2C1 corresponds to 1 set of PIN, the corresponding hardware pins are as follows:

I2C1 function

group0

I2C1_CLK

GPIO20

I2C1_SDA

GPIO21

4 Demo Introduction

The steps for executing demo1 are as follows:

1、Prepare the EEPROM module with the model number ZD24C128A and use the I2C1 connection method as follows:

Figure 1. i2c_connect_Diagram

2、Here are the commands in the order:
cpu1 i2c 1 init
[11:45:42.140]发→◇cpu1 i2c 1 init
[11:45:42.145]收←◆cpu1 i2c 1 init
os:I(6720):create shell_handle, tcb=28078db0, stack=[28077188-28078d88:7168], prio=5
$
$cpu1:i2c:I(6178):I2C(1) init ok, baud_rate:400000
cpu1:cli:I(6178):i2c(1) init
cpu1 i2c 1 memory_write 8 50 1//Write 8 bytes of data to EEPROM.
[11:45:43.027]发→◇cpu1 i2c 1 memory_write 8 50 1
[11:45:43.034]收←◆cpu1 i2c 1 memory_write 8 50 1
os:I(7608):create shell_handle, tcb=28078db0, stack=[28077188-28078d88:7168], prio=5
$
$cpu1:cli:I(7066):i2c(1) memory_write buf_len:8
cpu1 i2c 1 memory_read 8 50 1 //Read 8 bytes of data from EEPROM.
[11:45:44.825]发→◇cpu1 i2c 1 memory_read 8 50 1
[11:45:44.831]收←◆cpu1 i2c 1 memory_read 8 50 1
os:I(9406):create shell_handle, tcb=28078db0, stack=[28077188-28078d88:7168], prio=5
$
$cpu1:cli:I(8864):i2c_read_buf[0]=1
cpu1:cli:I(8864):i2c_read_buf[1]=2
cpu1:cli:I(8864):i2c_read_buf[2]=3
cpu1:cli:I(8864):i2c_read_buf[3]=4
cpu1:cli:I(8864):i2c_read_buf[4]=5
cpu1:cli:I(8864):i2c_read_buf[5]=6
cpu1:cli:I(8864):i2c_read_buf[6]=7
cpu1:cli:I(8864):i2c_read_buf[7]=8
cpu1:cli:I(8864):i2c(1) memory_read buf_len:8
3、Timing Diagram

Write Timing Diagram

Figure 2. i2c_wr_Sequence_ZD24C128A

read Timing Diagram

Figure 3. i2c_rd_Sequence_ZD24C128A

The steps for executing demo2 are as follows:

1、Prepare the EEPROM module with the model number FM24C04B and use the I2C1 connection method as follows:

Figure 4. i2c_connect_diagram

2、Here are the commands in the order:
cpu1 i2c 1 init
[16:44:55.619]发→◇cpu1 i2c 1 init
[16:44:55.622]收←◆cpu1 i2c 1 init
os:I(3120):create shell_handle, tcb=28078db0, stack=[28077188-28078d88:7168], prio=5
$
$cpu1:i2c:I(2984):I2C(1) init ok, baud_rate:400000
cpu1:cli:I(2984):i2c(1) init
cpu1 i2c 1 memory_write 8 50 0//Write 8 bytes of data to EEPROM.
[16:44:58.285]发→◇cpu1 i2c 1 memory_write 8 50 0
[16:44:58.292]收←◆cpu1 i2c 1 memory_write 8 50 0
os:I(5788):create shell_handle, tcb=28078db0, stack=[28077188-28078d88:7168], prio=5
$
$cpu1:cli:I(5652):i2c(1) memory_write buf_len:8
cpu1 i2c 1 memory_read 8 50 0 //Read 8 bytes of data from EEPROM.
[16:44:59.919]发→◇cpu1 i2c 1 memory_read 8 50 0
[16:44:59.926]收←◆cpu1 i2c 1 memory_read 8 50 0
os:I(7422):create shell_handle, tcb=28078db0, stack=[28077188-28078d88:7168], prio=5
$
$cpu1:cli:I(7286):i2c_read_buf[0]=1
cpu1:cli:I(7286):i2c_read_buf[1]=2
cpu1:cli:I(7286):i2c_read_buf[2]=3
cpu1:cli:I(7286):i2c_read_buf[3]=4
cpu1:cli:I(7286):i2c_read_buf[4]=5
cpu1:cli:I(7286):i2c_read_buf[5]=6
cpu1:cli:I(7286):i2c_read_buf[6]=7
cpu1:cli:I(7286):i2c_read_buf[7]=8
cpu1:cli:I(7286):i2c(1) memory_read buf_len:8
3、Timing Diagram

Write Timing Diagram

Figure 5. i2c_wr_Sequence_FM24C04B

Read Timing Diagram

Figure 6. i2c_rd_Sequence_FM24C04B

Note

Note: The dev_addr 50 in the memory_write command is in hexadecimal, because the i2c driver will shift the dev_addr one bit to the left. Therefore, the dev_addr passed in needs to be shifted one bit to the right from the actual dev_addr of ZD24C128A (1010b).