This section describes the resource requirements of the USB component.
The following section documents the requirements for the USB Device component. The actual requirements depend on the components used in the application and the configuration of these components.
The USB Device Core receives events sent from the interrupt service routine (ISR) of the USB Device Driver. The stack requirements for the ISR are typically less than 512 Bytes. The total stack space required for ISR depends on the interrupt nesting and therefore on the priority settings of these ISR.
Option (under section Stack Configuration) | Increase Value by |
---|---|
Stack Size (in Bytes) | + 512 for USB Device Driver |
User code that calls API functions of the USB Device Component should have a minimum of 512 Bytes of stack space available. Since API functions are frequently called from threads, the thread stack size should be at least 512 Bytes (see below).
Currently, the USB Device component works in two different RTOS configurations:
The USB Device component uses threads. Each instance of a component starts its own threads, for example two HID instances start two threads with the name: USBD_HID0_Thread, USBD_HID1_Thread. The thread execution starts with USBD_Initialize.
The following table lists the components, number of threads, thread name, default thread priority, default stack size and the configuration file with OS Resource Settings for stack size adjustments.
Component | Number of Threads | Thread Name | Default Priority | Default Stack Size | Configuration File |
---|---|---|---|---|---|
USB:Device | 1 | USBDn_Core_Thread | osPriorityAboveNormal | 1024 Bytes | USBD_Config_n.h |
USB:Device:ADC | 1 | USBD_ADCn_Thread | osPriorityAboveNormal | 512 Bytes | USBD_Config_ADC_n.h |
USB:Device:CDC | 2 | USBD_CDCn_Bulk_Thread, USBD_CDCn_Int_Thread | osPriorityAboveNormal | 512 Bytes | USBD_Config_CDC_n.h |
USB:Device:Custom Class | 1...15 | USBD_CustomClassn_EPm_Thread | osPriorityAboveNormal | 512 Bytes | USBD_Config_CustomClass_n.h |
USB:Device:HID | 1 | USBD_HIDn_Thread | osPriorityAboveNormal | 512 Bytes | USBD_Config_HID_n.h |
USB:Device:MSC | 1 | USBD_MSCn_Thread | osPriorityAboveNormal | 512 Bytes | USBD_Config_MSC_n.h |
n is the instance number, m is the endpoint number 1...15
The USB Device component allocates all necessary resources statically so no changes to RTX settings are necessary.
The following table shows the memory requirements for read-only (Flash) and read-write (RAM) memory. These numbers may be used to estimate the total size requirements of the application, but the actual numbers depend on compiler optimizations and target processor and may be therefore slightly different.
Component | RO Memory [Bytes] | RW Memory (Data) [Bytes] |
---|---|---|
USB:Core (Device) | 6.0 k | < 470 |
USB:Device:ADC | 2.5 k | < 110 + Audio Subframe Sizes * Buffer Sizes (configured in the USBD_Config_ADC_n.h) |
USB:Device:HID | 2.7 k | < 130 + Maximum Report Sizes (configured in the USBD_Config_HID_n.h) |
USB:Device:MSC | 4.1 k | < 160 + Maximum Bulk Buffer Size (configured in the USBD_Config_MSC_n.h) |
USB:Device:CDC ACM | 3.2 k | < 220 + Maximum Send/Receive Buffer Sizes (configured in the USBD_Config_CDC_n.h) |
USB:Device:Custom Class | 2.0 k | < 80 |
USB Device Driver | 1 .. 4 k | 0.5 .. 4 k |
The following section documents the requirements for the USB Host component. The actual requirements depend on the components used in the application and the configuration of these components.
The USB Host Core receives events sent from the interrupt service routine (ISR) of the USB Host Driver. The stack requirements for the ISR are typically less than 512 Bytes. The total stack space required for ISR depends on the interrupt nesting and therefore on the priority settings of these ISR.
Option (under section Stack Configuration) | Increase Value by |
---|---|
Stack Size (in Bytes) | + 512 for USB Host Driver |
User code that calls API functions of the USB Host Component should have a minimum of 512 Bytes of stack space available. Since API functions are frequently called from threads, the thread stack size should be at least 512 Bytes.
Currently, the USB Host component works in two different RTOS configurations:
The USB Host component uses threads. Each USB Host instance starts its own thread (USBHn_Core_Thread). The thread execution starts with USBH_Initialize. Additionally each instance of HID and CDC class also start their own thread (USBH_HIDn_IntIn_Thread or USBH_CDCn_IntIn_Thread) when HID or CDC device is connected.
The following table lists the components, number of threads, thread name, default thread priority, default stack size and the configuration file with OS Resource Settings for stack size adjustments.
Component | Number of Threads | Thread Name | Default Priority | Default Stack Size | Configuration File |
---|---|---|---|---|---|
USB:Host | 1 | USBHn_Core_Thread | osPriorityAboveNormal | 2048 Bytes | USBH_Config_n.h |
USB:Host:CDC | 1 | USBH_CDCn_IntIn_Thread | osPriorityAboveNormal | 512 Bytes | USBH_Config_CDC.h |
USB:Host:HID | 1 | USBH_HIDn_IntIn_Thread | osPriorityAboveNormal | 512 Bytes | USBH_Config_HID.h |
n is the instance number
The USB Host component allocates all necessary resources statically so no changes to RTX settings are necessary.
The following table shows the memory requirements for read-only (Flash) and read-write (RAM) memory. These numbers may be used to estimate the total size requirements of the application, but the actual numbers depend on compiler optimizations and target processor and may be therefore slightly different.
Component | RO Memory [Bytes] | RW Memory (Data) [Bytes] |
---|---|---|
USB:Core (Host) | < 9.5 k | < 370 + Memory Pool Size (configured in the USBH_Config_n.h) |
USB:Host:HID | < 1.3 k | < 70 |
USB:Host:MSC | < 3.4 k | < 40 |
USB:Host:CDC | < 1.0 k | < 30 |
USB Host OHCI support | < 3.5 k | < 0.5 k |
USB Host EHCI support | < 5.0 k | < 4.5 k |