diff --git a/MSOS_ESP/main/CMakeLists.txt b/MSOS_ESP/main/CMakeLists.txt
index cf3a33a..408786f 100644
--- a/MSOS_ESP/main/CMakeLists.txt
+++ b/MSOS_ESP/main/CMakeLists.txt
@@ -1,3 +1,3 @@
-idf_component_register(SRCS "hello_world_main.c" "iic.c" "oled.c" "state.c"
+idf_component_register(SRCS "hello_world_main.c" "iic.c" "oled.c" "state.c" "tca9535.c"
                        PRIV_REQUIRES spi_flash esp_driver_i2c log
                        INCLUDE_DIRS ".")
diff --git a/MSOS_ESP/main/hello_world_main.c b/MSOS_ESP/main/hello_world_main.c
index 5b172b2..7f17933 100644
--- a/MSOS_ESP/main/hello_world_main.c
+++ b/MSOS_ESP/main/hello_world_main.c
@@ -16,6 +16,7 @@
 #include "iic.h"
 #include "oled.h"
 #include "state.h"
+#include "tca9535.h"
 
 void app_main(void)
 {
@@ -48,6 +49,7 @@ void app_main(void)
 
     state_init();
     iic_init();
+    tca9535_init();
     oled_init();
 
     while(1){
diff --git a/MSOS_ESP/main/iic.c b/MSOS_ESP/main/iic.c
index 36a6a32..100be0e 100644
--- a/MSOS_ESP/main/iic.c
+++ b/MSOS_ESP/main/iic.c
@@ -53,6 +53,18 @@ esp_err_t iic_send_bytes(unsigned char addr, unsigned char *txd, unsigned int le
     return i2c_master_transmit(s_iic_dev, (const uint8_t *)txd, (size_t)len, IIC_TIMEOUT_MS);
 }
 
+esp_err_t iic_read_reg(unsigned char addr, unsigned char reg, unsigned char *rxd, unsigned int len)
+{
+    if (rxd == NULL || len == 0 || s_iic_dev == NULL) {
+        return ESP_ERR_INVALID_STATE;
+    }
+    esp_err_t ret = i2c_master_device_change_address(s_iic_dev, (uint16_t)addr, IIC_TIMEOUT_MS);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+    return i2c_master_transmit_receive(s_iic_dev, &reg, 1, rxd, len, IIC_TIMEOUT_MS);
+}
+
 unsigned char iic_read_byte(unsigned char addr)
 {
     uint8_t byte = 0;
diff --git a/MSOS_ESP/main/iic.h b/MSOS_ESP/main/iic.h
index 3cf6262..581d2e2 100644
--- a/MSOS_ESP/main/iic.h
+++ b/MSOS_ESP/main/iic.h
@@ -12,6 +12,7 @@
 esp_err_t iic_init(void);
 void iic_scan(void);
 esp_err_t iic_send_bytes(unsigned char addr, unsigned char *txd, unsigned int len);
+esp_err_t iic_read_reg(unsigned char addr, unsigned char reg, unsigned char *rxd, unsigned int len);
 unsigned char iic_read_byte(unsigned char addr);
 
 #endif
diff --git a/MSOS_ESP/main/tca9535.c b/MSOS_ESP/main/tca9535.c
new file mode 100644
index 0000000..0eceb2b
--- /dev/null
+++ b/MSOS_ESP/main/tca9535.c
@@ -0,0 +1,148 @@
+#include "tca9535.h"
+#include "iic.h"
+#include "esp_log.h"
+
+static const char *TAG = "TCA9535";
+
+esp_err_t tca9535_read_reg(uint8_t reg, uint8_t *val)
+{
+    if (val == NULL) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    return iic_read_reg(TCA9535_ADDRESS, reg, val, 1);
+}
+
+esp_err_t tca9535_write_reg(uint8_t reg, uint8_t val)
+{
+    unsigned char buf[2] = {reg, val};
+    return iic_send_bytes(TCA9535_ADDRESS, buf, 2);
+}
+
+esp_err_t tca9535_set_dir(uint16_t dir)
+{
+    esp_err_t ret = tca9535_write_reg(TCA9535_REG_CONFIG0, (uint8_t)(dir & 0xFF));
+    if (ret != ESP_OK) {
+        return ret;
+    }
+    return tca9535_write_reg(TCA9535_REG_CONFIG1, (uint8_t)(dir >> 8));
+}
+
+esp_err_t tca9535_set_output(uint16_t val)
+{
+    esp_err_t ret = tca9535_write_reg(TCA9535_REG_OUTPUT0, (uint8_t)(val & 0xFF));
+    if (ret != ESP_OK) {
+        return ret;
+    }
+    return tca9535_write_reg(TCA9535_REG_OUTPUT1, (uint8_t)(val >> 8));
+}
+
+esp_err_t tca9535_get_output(uint16_t *val)
+{
+    if (val == NULL) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    uint8_t p0 = 0, p1 = 0;
+    esp_err_t ret = tca9535_read_reg(TCA9535_REG_OUTPUT0, &p0);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+    ret = tca9535_read_reg(TCA9535_REG_OUTPUT1, &p1);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+    *val = (uint16_t)p0 | ((uint16_t)p1 << 8);
+    return ESP_OK;
+}
+
+esp_err_t tca9535_get_input(uint16_t *val)
+{
+    if (val == NULL) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    uint8_t p0 = 0, p1 = 0;
+    esp_err_t ret = tca9535_read_reg(TCA9535_REG_INPUT0, &p0);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+    ret = tca9535_read_reg(TCA9535_REG_INPUT1, &p1);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+    *val = (uint16_t)p0 | ((uint16_t)p1 << 8);
+    return ESP_OK;
+}
+
+esp_err_t tca9535_pin_mode(uint8_t pin, uint8_t mode)
+{
+    if (pin >= TCA9535_PIN_COUNT) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    uint8_t reg = (pin < 8) ? TCA9535_REG_CONFIG0 : TCA9535_REG_CONFIG1;
+    uint8_t bit = pin & 0x07;
+    uint8_t cur = 0;
+    esp_err_t ret = tca9535_read_reg(reg, &cur);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+    if (mode == TCA9535_INPUT) {
+        cur |= (1 << bit);
+    } else {
+        cur &= ~(1 << bit);
+    }
+    return tca9535_write_reg(reg, cur);
+}
+
+esp_err_t tca9535_digital_write(uint8_t pin, uint8_t val)
+{
+    if (pin >= TCA9535_PIN_COUNT) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    uint8_t reg = (pin < 8) ? TCA9535_REG_OUTPUT0 : TCA9535_REG_OUTPUT1;
+    uint8_t bit = pin & 0x07;
+    uint8_t cur = 0;
+    esp_err_t ret = tca9535_read_reg(reg, &cur);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+    if (val) {
+        cur |= (1 << bit);
+    } else {
+        cur &= ~(1 << bit);
+    }
+    return tca9535_write_reg(reg, cur);
+}
+
+esp_err_t tca9535_digital_read(uint8_t pin, uint8_t *val)
+{
+    if (pin >= TCA9535_PIN_COUNT || val == NULL) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    uint8_t reg = (pin < 8) ? TCA9535_REG_INPUT0 : TCA9535_REG_INPUT1;
+    uint8_t bit = pin & 0x07;
+    uint8_t cur = 0;
+    esp_err_t ret = tca9535_read_reg(reg, &cur);
+    if (ret != ESP_OK) {
+        return ret;
+    }
+    *val = (cur >> bit) & 0x01;
+    return ESP_OK;
+}
+
+esp_err_t tca9535_init(void)
+{
+    esp_err_t ret = tca9535_write_reg(TCA9535_REG_POLARITY0, 0x00);
+    if (ret != ESP_OK) {
+        ESP_LOGE(TAG, "TCA9535初始化失败");
+        return ret;
+    }
+    tca9535_write_reg(TCA9535_REG_POLARITY1, 0x00);
+    tca9535_write_reg(TCA9535_REG_OUTPUT0, 0x00);
+    tca9535_write_reg(TCA9535_REG_OUTPUT1, 0x00);
+    ret = tca9535_set_dir(0xFFFF);
+    if (ret != ESP_OK) {
+        ESP_LOGE(TAG, "TCA9535初始化失败");
+        return ret;
+    }
+    ESP_LOGI(TAG, "TCA9535初始化成功, 地址0x%02X", TCA9535_ADDRESS);
+    return ESP_OK;
+}
diff --git a/MSOS_ESP/main/tca9535.h b/MSOS_ESP/main/tca9535.h
new file mode 100644
index 0000000..061c007
--- /dev/null
+++ b/MSOS_ESP/main/tca9535.h
@@ -0,0 +1,37 @@
+#ifndef TCA9535_H_
+#define TCA9535_H_
+
+#include "esp_err.h"
+#include <stdint.h>
+
+#define TCA9535_ADDRESS     0x20
+
+#define TCA9535_REG_INPUT0      0x00
+#define TCA9535_REG_INPUT1      0x01
+#define TCA9535_REG_OUTPUT0     0x02
+#define TCA9535_REG_OUTPUT1     0x03
+#define TCA9535_REG_POLARITY0   0x04
+#define TCA9535_REG_POLARITY1   0x05
+#define TCA9535_REG_CONFIG0     0x06
+#define TCA9535_REG_CONFIG1     0x07
+
+#define TCA9535_INPUT   1
+#define TCA9535_OUTPUT  0
+
+#define TCA9535_PIN_COUNT   16
+
+esp_err_t tca9535_init(void);
+
+esp_err_t tca9535_read_reg(uint8_t reg, uint8_t *val);
+esp_err_t tca9535_write_reg(uint8_t reg, uint8_t val);
+
+esp_err_t tca9535_set_dir(uint16_t dir);
+esp_err_t tca9535_set_output(uint16_t val);
+esp_err_t tca9535_get_output(uint16_t *val);
+esp_err_t tca9535_get_input(uint16_t *val);
+
+esp_err_t tca9535_pin_mode(uint8_t pin, uint8_t mode);
+esp_err_t tca9535_digital_write(uint8_t pin, uint8_t val);
+esp_err_t tca9535_digital_read(uint8_t pin, uint8_t *val);
+
+#endif