Merge pull request #2276 from hathach/more-esp32-max3421

More max3421

.idea/cmake.xml

@@ -9,7 +9,7 @@
           </envs>
         </ADDITIONAL_GENERATION_ENVIRONMENT>
       </configuration>
-      <configuration PROFILE_NAME="kaluga" ENABLED="true" TOOLCHAIN_NAME="ESP-IDF" GENERATION_OPTIONS="-DBOARD=espressif_kaluga_1 -DMAX3421_HOST=1 -DLOG=2">
+      <configuration PROFILE_NAME="kaluga" ENABLED="false" TOOLCHAIN_NAME="ESP-IDF" GENERATION_OPTIONS="-DBOARD=espressif_kaluga_1 -DMAX3421_HOST=1 -DLOG=2">
         <ADDITIONAL_GENERATION_ENVIRONMENT>
           <envs>
             <env name="ESPBAUD" value="1500000" />
@@ -54,16 +54,16 @@
       <configuration PROFILE_NAME="ra6m5 PORT0" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=ra6m5_ek -DLOG=3 -DLOGGER=RTT -DTRACE_ETM=1 -DPORT=0" />
       <configuration PROFILE_NAME="uno_r4" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=uno_r4 -DLOG=4 -DLOGGER=RTT" />
       <configuration PROFILE_NAME="portenta_c33" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=portenta_c33 -DLOG=3" />
-      <configuration PROFILE_NAME="metro_m4_express" ENABLED="true" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=metro_m4_express -DLOG=3 -DLOGGER=RTT -DMAX3421_HOST=1" />
+      <configuration PROFILE_NAME="metro_m4_express" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=metro_m4_express -DLOG=3 -DLOGGER=RTT -DMAX3421_HOST=1" />
       <configuration PROFILE_NAME="metro_m0_express" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=metro_m0_express -DLOG=3 -DLOGGER=RTT -DMAX3421_HOST=1" />
-      <configuration PROFILE_NAME="stm32u5" ENABLED="true" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=stm32u575eval" />
+      <configuration PROFILE_NAME="stm32u5" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=stm32u575eval" />
       <configuration PROFILE_NAME="metro esp32s2" ENABLED="false" TOOLCHAIN_NAME="ESP-IDF" GENERATION_OPTIONS="-DBOARD=adafruit_metro_esp32s2 -DMAX3421_HOST=1 -DLOG=2">
-            <ADDITIONAL_GENERATION_ENVIRONMENT>
+        <ADDITIONAL_GENERATION_ENVIRONMENT>
-                <envs>
+          <envs>
-                    <env name="ESPBAUD" value="1500000" />
+            <env name="ESPBAUD" value="1500000" />
-                </envs>
+          </envs>
-            </ADDITIONAL_GENERATION_ENVIRONMENT>
+        </ADDITIONAL_GENERATION_ENVIRONMENT>
-        </configuration>
+      </configuration>
     </configurations>
   </component>
 </project>

hw/bsp/espressif/boards/family.c

@@ -38,22 +38,31 @@
 #if ESP_IDF_VERSION_MAJOR > 4
   #include "esp_private/periph_ctrl.h"
 #else
+
   #include "driver/periph_ctrl.h"
+
 #endif
 
+// Note; current code use UART0 can cause device to reset while monitoring
+#define USE_UART  0
 #define UART_ID  UART_NUM_0
 
 #ifdef NEOPIXEL_PIN
+
 #include "led_strip.h"
-static led_strip_t *strip;
+
+static led_strip_t* strip;
 #endif
 
 #if CFG_TUH_ENABLED && CFG_TUH_MAX3421
+
 #include "driver/spi_master.h"
+
 static void max3421_init(void);
+
 #endif
 
-static void configure_pins(usb_hal_context_t *usb);
+static void configure_pins(usb_hal_context_t* usb);
 
 //--------------------------------------------------------------------+
 // Implementation
@@ -61,6 +70,7 @@ static void configure_pins(usb_hal_context_t *usb);
 
 // Initialize on-board peripherals : led, button, uart and USB
 void board_init(void) {
+#if USE_UART
   // uart init
   uart_config_t uart_config = {
       .baud_rate = 115200,
@@ -71,6 +81,7 @@ void board_init(void) {
   };
   uart_driver_install(UART_ID, 1024, 0, 0, NULL, 0);
   uart_param_config(UART_ID, &uart_config);
+#endif
 
 #ifdef NEOPIXEL_PIN
   #ifdef NEOPIXEL_POWER_PIN
@@ -111,11 +122,11 @@ void board_init(void) {
 #endif
 }
 
-static void configure_pins(usb_hal_context_t *usb) {
+static void configure_pins(usb_hal_context_t* usb) {
   /* usb_periph_iopins currently configures USB_OTG as USB Device.
    * Introduce additional parameters in usb_hal_context_t when adding support
    * for USB Host. */
-  for (const usb_iopin_dsc_t *iopin = usb_periph_iopins; iopin->pin != -1; ++iopin) {
+  for (const usb_iopin_dsc_t* iopin = usb_periph_iopins; iopin->pin != -1; ++iopin) {
     if ((usb->use_external_phy) || (iopin->ext_phy_only == 0)) {
       esp_rom_gpio_pad_select_gpio(iopin->pin);
       if (iopin->is_output) {
@@ -156,20 +167,24 @@ uint32_t board_button_read(void) {
 }
 
 // Get characters from UART
-int board_uart_read(uint8_t *buf, int len) {
+int board_uart_read(uint8_t* buf, int len) {
+#if USE_UART
   return uart_read_bytes(UART_ID, buf, len, 0);
+#else
+  return -1;
+#endif
 }
 
 // Send characters to UART
-int board_uart_write(void const *buf, int len) {
+int board_uart_write(void const* buf, int len) {
   (void) buf;
   (void) len;
   return 0;
 }
 
 int board_getchar(void) {
-  char c;
+  uint8_t c = 0;
-  return (uart_read_bytes(UART_ID, &c, 1, 0) > 0) ? (int) c : (-1);
+  return board_uart_read(&c, 1) > 0 ? (int) c : (-1);
 }
 
 //--------------------------------------------------------------------+
@@ -208,7 +223,7 @@ static void max3421_init(void) {
   gpio_set_level(MAX3421_CS_PIN, 1);
 
   // SPI
-  spi_bus_config_t buscfg={
+  spi_bus_config_t buscfg = {
       .miso_io_num = MAX3421_MISO_PIN,
       .mosi_io_num = MAX3421_MOSI_PIN,
       .sclk_io_num = MAX3421_SCK_PIN,
@@ -220,15 +235,15 @@ static void max3421_init(void) {
       .data7_io_num = -1,
       .max_transfer_sz = 1024
   };
-  ESP_ERROR_CHECK( spi_bus_initialize(MAX3421_SPI_HOST, &buscfg, SPI_DMA_CH_AUTO) );
+  ESP_ERROR_CHECK(spi_bus_initialize(MAX3421_SPI_HOST, &buscfg, SPI_DMA_CH_AUTO));
 
   spi_device_interface_config_t max3421_cfg = {
       .mode = 0,
-      .clock_speed_hz = 4000000, // 26000000
+      .clock_speed_hz = 26000000,
       .spics_io_num = -1, // manual control CS
       .queue_size = 1
   };
-  ESP_ERROR_CHECK( spi_bus_add_device(MAX3421_SPI_HOST, &max3421_cfg, &max3421_spi) );
+  ESP_ERROR_CHECK(spi_bus_add_device(MAX3421_SPI_HOST, &max3421_cfg, &max3421_spi));
 
   // debug
   gpio_set_direction(13, GPIO_MODE_OUTPUT);
@@ -236,7 +251,7 @@ static void max3421_init(void) {
 
   // Interrupt pin
   max3421_intr_sem = xSemaphoreCreateBinary();
-  xTaskCreate(max3421_intr_task, "max3421 intr", 2048, NULL, configMAX_PRIORITIES-2, NULL);
+  xTaskCreate(max3421_intr_task, "max3421 intr", 2048, NULL, configMAX_PRIORITIES - 2, NULL);
 
   gpio_set_direction(MAX3421_INTR_PIN, GPIO_MODE_INPUT);
   gpio_set_intr_type(MAX3421_INTR_PIN, GPIO_INTR_NEGEDGE);
@@ -259,18 +274,20 @@ void tuh_max3421_spi_cs_api(uint8_t rhport, bool active) {
   gpio_set_level(MAX3421_CS_PIN, active ? 0 : 1);
 }
 
-bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const *tx_buf, size_t tx_len, uint8_t *rx_buf, size_t rx_len) {
+bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const* tx_buf, uint8_t* rx_buf, size_t xfer_bytes) {
   (void) rhport;
 
-  if (tx_len == 0) {
+  if (tx_buf == NULL) {
     // fifo read, transmit rx_buf as dummy
     tx_buf = rx_buf;
-    tx_len = rx_len;
   }
 
+  // length in bits
+  size_t const len_bits = xfer_bytes << 3;
+
   spi_transaction_t xact = {
-      .length = tx_len << 3, // length in bits
+      .length = len_bits,
-      .rxlength = rx_len << 3, // length in bits
+      .rxlength = rx_buf ? len_bits : 0,
       .tx_buffer = tx_buf,
       .rx_buffer = rx_buf
   };

hw/bsp/nrf/boards/feather_nrf52840_express/board.cmake

@@ -1,6 +1,6 @@
 set(MCU_VARIANT nrf52840)
-#set(LD_FILE_GNU ${CMAKE_CURRENT_LIST_DIR}/../../linker/nrf52840_s140_v6.ld)
+set(LD_FILE_GNU ${CMAKE_CURRENT_LIST_DIR}/../../linker/nrf52840_s140_v6.ld)
-set(LD_FILE_GNU ${NRFX_DIR}/mdk/nrf52840_xxaa.ld)
+#set(LD_FILE_GNU ${NRFX_DIR}/mdk/nrf52840_xxaa.ld)
 
 # enable max3421 host driver for this board
 set(MAX3421_HOST 1)

hw/bsp/nrf/boards/feather_nrf52840_express/board.h

@@ -49,8 +49,8 @@
 #define MAX3421_SCK_PIN  14
 #define MAX3421_MOSI_PIN 13
 #define MAX3421_MISO_PIN 15
-#define MAX3421_CS_PIN   27
+#define MAX3421_CS_PIN   27 // D10
-#define MAX3421_INTR_PIN 26
+#define MAX3421_INTR_PIN 26 // D9
 
 #ifdef __cplusplus
  }

hw/bsp/nrf/family.c

@@ -95,7 +95,9 @@ TU_ATTR_UNUSED static void power_event_handler(nrfx_power_usb_evt_t event) {
 
 //------------- Host using MAX2341E -------------//
 #if CFG_TUH_ENABLED && defined(CFG_TUH_MAX3421) && CFG_TUH_MAX3421
+
 static void max3421_init(void);
+
 static nrfx_spim_t _spi = NRFX_SPIM_INSTANCE(1);
 #endif
 
@@ -203,15 +205,15 @@ uint32_t board_button_read(void) {
   return BUTTON_STATE_ACTIVE == nrf_gpio_pin_read(BUTTON_PIN);
 }
 
-int board_uart_read(uint8_t *buf, int len) {
+int board_uart_read(uint8_t* buf, int len) {
   (void) buf;
   (void) len;
   return 0;
 //  return NRFX_SUCCESS == nrfx_uart_rx(&_uart_id, buf, (size_t) len) ? len : 0;
 }
 
-int board_uart_write(void const *buf, int len) {
+int board_uart_write(void const* buf, int len) {
-  return (NRFX_SUCCESS == nrfx_uarte_tx(&_uart_id, (uint8_t const *) buf, (size_t) len)) ? len : 0;
+  return (NRFX_SUCCESS == nrfx_uarte_tx(&_uart_id, (uint8_t const*) buf, (size_t) len)) ? len : 0;
 }
 
 #if CFG_TUSB_OS == OPT_OS_NONE
@@ -323,6 +325,7 @@ static void max3421_init(void) {
   nrfx_gpiote_trigger_enable(MAX3421_INTR_PIN, true);
 }
 
+// API to enable/disable MAX3421 INTR pin interrupt
 void tuh_max3421_int_api(uint8_t rhport, bool enabled) {
   (void) rhport;
 
@@ -335,22 +338,25 @@ void tuh_max3421_int_api(uint8_t rhport, bool enabled) {
   }
 }
 
+// API to control MAX3421 SPI CS
 void tuh_max3421_spi_cs_api(uint8_t rhport, bool active) {
   (void) rhport;
   nrf_gpio_pin_write(MAX3421_CS_PIN, active ? 0 : 1);
 }
 
-bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const *tx_buf, size_t tx_len, uint8_t *rx_buf, size_t rx_len) {
+// API to transfer data with MAX3421 SPI
+// Either tx_buf or rx_buf can be NULL, which means transfer is write or read only
+bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const* tx_buf, uint8_t* rx_buf, size_t xfer_bytes) {
   (void) rhport;
 
   nrfx_spim_xfer_desc_t xfer = {
       .p_tx_buffer = tx_buf,
-      .tx_length   = tx_len,
+      .tx_length   = tx_buf ? xfer_bytes : 0,
       .p_rx_buffer = rx_buf,
-      .rx_length   = rx_len,
+      .rx_length   = rx_buf ? xfer_bytes : 0,
   };
 
-  return (nrfx_spim_xfer(&_spi, &xfer, 0) == NRFX_SUCCESS);
+  return nrfx_spim_xfer(&_spi, &xfer, 0) == NRFX_SUCCESS;
 }
 
 #endif

hw/bsp/samd21/family.c

@@ -72,6 +72,7 @@ static void uart_init(void);
 #define MAX3421_SERCOM TU_XSTRCAT(SERCOM, MAX3421_SERCOM_ID)
 
 static void max3421_init(void);
+
 #endif
 
 void board_init(void) {
@@ -237,13 +238,13 @@ int board_uart_write(void const * buf, int len)
 static void uart_init(void) {
 }
 
-int board_uart_read(uint8_t *buf, int len) {
+int board_uart_read(uint8_t* buf, int len) {
   (void) buf;
   (void) len;
   return 0;
 }
 
-int board_uart_write(void const *buf, int len) {
+int board_uart_write(void const* buf, int len) {
   (void) buf;
   (void) len;
   return 0;
@@ -261,6 +262,7 @@ void SysTick_Handler(void) {
 uint32_t board_millis(void) {
   return system_ticks;
 }
+
 #endif
 
 //--------------------------------------------------------------------+
@@ -278,8 +280,8 @@ static void max3421_init(void) {
 
   // Configure GCLK for SERCOM
 //  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID_SERCOM4_CORE | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_CLKEN;
-  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(GCLK_CLKCTRL_ID_SERCOM0_CORE_Val+MAX3421_SERCOM_ID) |
+  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(GCLK_CLKCTRL_ID_SERCOM0_CORE_Val + MAX3421_SERCOM_ID) |
-      GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_CLKEN;
+                      GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_CLKEN;
   while (GCLK->STATUS.bit.SYNCBUSY);
 
   Sercom* sercom = MAX3421_SERCOM;
@@ -293,7 +295,7 @@ static void max3421_init(void) {
 
   // Set up SPI in master mode, MSB first, SPI mode 0
   sercom->SPI.CTRLA.reg = SERCOM_SPI_CTRLA_DOPO(MAX3421_TX_PAD) | SERCOM_SPI_CTRLA_DIPO(MAX3421_RX_PAD) |
-      SERCOM_SPI_CTRLA_MODE(3);
+                          SERCOM_SPI_CTRLA_MODE(3);
 
   sercom->SPI.CTRLB.reg = SERCOM_SPI_CTRLB_CHSIZE(0) | SERCOM_SPI_CTRLB_RXEN;
   while (sercom->SPI.SYNCBUSY.bit.CTRLB == 1);
@@ -366,6 +368,7 @@ void EIC_Handler(void) {
   tuh_int_handler(1, true);
 }
 
+// API to enable/disable MAX3421 INTR pin interrupt
 void tuh_max3421_int_api(uint8_t rhport, bool enabled) {
   (void) rhport;
 
@@ -376,24 +379,26 @@ void tuh_max3421_int_api(uint8_t rhport, bool enabled) {
   }
 }
 
+// API to control MAX3421 SPI CS
 void tuh_max3421_spi_cs_api(uint8_t rhport, bool active) {
   (void) rhport;
   gpio_set_pin_level(MAX3421_CS_PIN, active ? 0 : 1);
 }
 
-bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const *tx_buf, size_t tx_len, uint8_t *rx_buf, size_t rx_len) {
+// API to transfer data with MAX3421 SPI
+// Either tx_buf or rx_buf can be NULL, which means transfer is write or read only
+bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const* tx_buf, uint8_t* rx_buf, size_t xfer_bytes) {
   (void) rhport;
 
   Sercom* sercom = MAX3421_SERCOM;
 
-  size_t count = 0;
+  for (size_t count = 0; count < xfer_bytes; count++) {
-  while (count < tx_len || count < rx_len) {
     // Wait for the transmit buffer to be empty
     while (!sercom->SPI.INTFLAG.bit.DRE);
 
     // Write data to be transmitted
     uint8_t data = 0x00;
-    if (count < tx_len) {
+    if (tx_buf) {
       data = tx_buf[count];
     }
 
@@ -404,11 +409,9 @@ bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const *tx_buf, size_t tx_l
 
     // Read received data
     data = (uint8_t) sercom->SPI.DATA.reg;
-    if (count < rx_len) {
+    if (rx_buf) {
       rx_buf[count] = data;
     }
-
-    count++;
   }
 
   // wait for bus idle and clear flags

hw/bsp/samd51/family.c

@@ -81,6 +81,7 @@ void USB_3_Handler(void) {
 #define MAX3421_EIC_Handler TU_XSTRCAT3(EIC_, MAX3421_INTR_EIC_ID, _Handler)
 
 static void max3421_init(void);
+
 #endif
 
 void board_init(void) {
@@ -153,13 +154,13 @@ uint32_t board_button_read(void) {
   return gpio_get_pin_level(BUTTON_PIN) ? 0 : 1;
 }
 
-int board_uart_read(uint8_t *buf, int len) {
+int board_uart_read(uint8_t* buf, int len) {
   (void) buf;
   (void) len;
   return 0;
 }
 
-int board_uart_write(void const *buf, int len) {
+int board_uart_write(void const* buf, int len) {
   (void) buf;
   (void) len;
   return 0;
@@ -175,6 +176,7 @@ void SysTick_Handler(void) {
 uint32_t board_millis(void) {
   return system_ticks;
 }
+
 #endif
 
 //--------------------------------------------------------------------+
@@ -189,7 +191,7 @@ static void max3421_init(void) {
   uint32_t const baudrate = 12000000u;
 
   struct {
-    volatile uint32_t *mck_apb;
+    volatile uint32_t* mck_apb;
     uint32_t mask;
     uint8_t gclk_id_core;
     uint8_t gclk_id_slow;
@@ -214,8 +216,10 @@ static void max3421_init(void) {
   *sercom_clock[MAX3421_SERCOM_ID].mck_apb |= sercom_clock[MAX3421_SERCOM_ID].mask;
 
   // Configure GCLK for SERCOM
-  GCLK->PCHCTRL[sercom_clock[MAX3421_SERCOM_ID].gclk_id_core].reg = GCLK_PCHCTRL_GEN_GCLK0_Val | (1 << GCLK_PCHCTRL_CHEN_Pos);
+  GCLK->PCHCTRL[sercom_clock[MAX3421_SERCOM_ID].gclk_id_core].reg =
-  GCLK->PCHCTRL[sercom_clock[MAX3421_SERCOM_ID].gclk_id_slow].reg = GCLK_PCHCTRL_GEN_GCLK3_Val | (1 << GCLK_PCHCTRL_CHEN_Pos);
+      GCLK_PCHCTRL_GEN_GCLK0_Val | (1 << GCLK_PCHCTRL_CHEN_Pos);
+  GCLK->PCHCTRL[sercom_clock[MAX3421_SERCOM_ID].gclk_id_slow].reg =
+      GCLK_PCHCTRL_GEN_GCLK3_Val | (1 << GCLK_PCHCTRL_CHEN_Pos);
 
   // Disable the SPI module
   sercom->SPI.CTRLA.bit.ENABLE = 0;
@@ -226,7 +230,7 @@ static void max3421_init(void) {
 
   // Set up SPI in master mode, MSB first, SPI mode 0
   sercom->SPI.CTRLA.reg = SERCOM_SPI_CTRLA_DOPO(MAX3421_TX_PAD) | SERCOM_SPI_CTRLA_DIPO(MAX3421_RX_PAD) |
-      SERCOM_SPI_CTRLA_MODE(3);
+                          SERCOM_SPI_CTRLA_MODE(3);
 
   sercom->SPI.CTRLB.reg = SERCOM_SPI_CTRLB_CHSIZE(0) | SERCOM_SPI_CTRLB_RXEN;
   while (sercom->SPI.SYNCBUSY.bit.CTRLB == 1);
@@ -278,9 +282,9 @@ static void max3421_init(void) {
   while (EIC->SYNCBUSY.bit.ENABLE);
 
   // Configure EIC to trigger on falling edge
-  volatile uint32_t * eic_config;
+  volatile uint32_t* eic_config;
   uint8_t sense_shift;
-  if ( MAX3421_INTR_EIC_ID < 8 ) {
+  if (MAX3421_INTR_EIC_ID < 8) {
     eic_config = &EIC->CONFIG[0].reg;
     sense_shift = MAX3421_INTR_EIC_ID * 4;
   } else {
@@ -312,6 +316,7 @@ void MAX3421_EIC_Handler(void) {
   tuh_int_handler(1, true);
 }
 
+// API to enable/disable MAX3421 INTR pin interrupt
 void tuh_max3421_int_api(uint8_t rhport, bool enabled) {
   (void) rhport;
 
@@ -323,24 +328,26 @@ void tuh_max3421_int_api(uint8_t rhport, bool enabled) {
   }
 }
 
+// API to control MAX3421 SPI CS
 void tuh_max3421_spi_cs_api(uint8_t rhport, bool active) {
   (void) rhport;
   gpio_set_pin_level(MAX3421_CS_PIN, active ? 0 : 1);
 }
 
-bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const *tx_buf, size_t tx_len, uint8_t *rx_buf, size_t rx_len) {
+// API to transfer data with MAX3421 SPI
+// Either tx_buf or rx_buf can be NULL, which means transfer is write or read only
+bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const* tx_buf, uint8_t* rx_buf, size_t xfer_bytes) {
   (void) rhport;
 
   Sercom* sercom = MAX3421_SERCOM;
 
-  size_t count = 0;
+  for (size_t count = 0; count < xfer_bytes; count++) {
-  while (count < tx_len || count < rx_len) {
     // Wait for the transmit buffer to be empty
     while (!sercom->SPI.INTFLAG.bit.DRE);
 
     // Write data to be transmitted
     uint8_t data = 0x00;
-    if (count < tx_len) {
+    if (tx_buf) {
       data = tx_buf[count];
     }
 
@@ -351,11 +358,9 @@ bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const *tx_buf, size_t tx_l
 
     // Read received data
     data = (uint8_t) sercom->SPI.DATA.reg;
-    if (count < rx_len) {
+    if (rx_buf) {
       rx_buf[count] = data;
     }
-
-    count++;
   }
 
   // wait for bus idle and clear flags

src/portable/analog/max3421/hcd_max3421.c

@@ -210,16 +210,21 @@ static max3421_data_t _hcd_data;
 // API: SPI transfer with MAX3421E, must be implemented by application
 //--------------------------------------------------------------------+
 
-void tuh_max3421_spi_cs_api(uint8_t rhport, bool active);
+// API to control MAX3421 SPI CS
-bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const * tx_buf, size_t tx_len, uint8_t * rx_buf, size_t rx_len);
+extern void tuh_max3421_spi_cs_api(uint8_t rhport, bool active);
-void tuh_max3421_int_api(uint8_t rhport, bool enabled);
 
-static void handle_connect_irq(uint8_t rhport, bool in_isr);
+// API to transfer data with MAX3421 SPI
-static inline void hirq_write(uint8_t rhport, uint8_t data, bool in_isr);
+// Either tx_buf or rx_buf can be NULL, which means transfer is write or read only
+extern bool tuh_max3421_spi_xfer_api(uint8_t rhport, uint8_t const* tx_buf, uint8_t* rx_buf, size_t xfer_bytes);
+
+// API to enable/disable MAX3421 INTR pin interrupt
+extern void tuh_max3421_int_api(uint8_t rhport, bool enabled);
 
 //--------------------------------------------------------------------+
 // SPI Helper
 //--------------------------------------------------------------------+
+static void handle_connect_irq(uint8_t rhport, bool in_isr);
+static inline void hirq_write(uint8_t rhport, uint8_t data, bool in_isr);
 
 static void max3421_spi_lock(uint8_t rhport, bool in_isr) {
   // disable interrupt and mutex lock (for pre-emptive RTOS) if not in_isr
@@ -249,9 +254,9 @@ static void fifo_write(uint8_t rhport, uint8_t reg, uint8_t const * buffer, uint
 
   max3421_spi_lock(rhport, in_isr);
 
-  tuh_max3421_spi_xfer_api(rhport, &reg, 1, &hirq, 1);
+  tuh_max3421_spi_xfer_api(rhport, &reg, &hirq, 1);
   _hcd_data.hirq = hirq;
-  tuh_max3421_spi_xfer_api(rhport, buffer, len, NULL, 0);
+  tuh_max3421_spi_xfer_api(rhport, buffer, NULL, len);
 
   max3421_spi_unlock(rhport, in_isr);
 
@@ -263,9 +268,9 @@ static void fifo_read(uint8_t rhport, uint8_t * buffer, uint16_t len, bool in_is
 
   max3421_spi_lock(rhport, in_isr);
 
-  tuh_max3421_spi_xfer_api(rhport, &reg, 1, &hirq, 1);
+  tuh_max3421_spi_xfer_api(rhport, &reg, &hirq, 1);
   _hcd_data.hirq = hirq;
-  tuh_max3421_spi_xfer_api(rhport, NULL, 0, buffer, len);
+  tuh_max3421_spi_xfer_api(rhport, NULL, buffer, len);
 
   max3421_spi_unlock(rhport, in_isr);
 }
@@ -276,7 +281,7 @@ static void reg_write(uint8_t rhport, uint8_t reg, uint8_t data, bool in_isr) {
 
   max3421_spi_lock(rhport, in_isr);
 
-  tuh_max3421_spi_xfer_api(rhport, tx_buf, 2, rx_buf, 2);
+  tuh_max3421_spi_xfer_api(rhport, tx_buf, rx_buf, 2);
 
   max3421_spi_unlock(rhport, in_isr);
 
@@ -290,7 +295,7 @@ static uint8_t reg_read(uint8_t rhport, uint8_t reg, bool in_isr) {
 
   max3421_spi_lock(rhport, in_isr);
 
-  bool ret = tuh_max3421_spi_xfer_api(rhport, tx_buf, 2, rx_buf, 2);
+  bool ret = tuh_max3421_spi_xfer_api(rhport, tx_buf, rx_buf, 2);
 
   max3421_spi_unlock(rhport, in_isr);