S3C2440 WINCE6 changes USB DEVICE to USB HOST and implements two USB HOSTs

The default configuration of S3C2440 is generally one USB DEVICE and one USB HOST, that is, one master port and one slave port. Let's first take a look at the knowledge related to USB Device and USB Host.

USB Host:

The bottom layer is the USB Host controller, and the upper layer is the USB Host Controller Driver, which is responsible for communicating with the hardware to transmit data. In WinCE, it supports UHCI, OHCI, and EHCI. The Host Core Driver & Hub Driver is a USB protocol stack independent of the hardware, supporting the USB Host protocol and USB Hub functions. The top layer is the USB Host Class driver, which is the application protocol of the USB Host. Currently, in WinCE, it supports four applications: RNDIS, Print, Mass Storage, and HID.

USB Device:

The bottom layer is the USB Device controller, and the upper layer is the USB Device Driver responsible for communicating with the hardware. The Device Core Driver is the protocol stack of the USB Device. The top layer is the application layer of the USB Device, which currently supports three applications in WinCE: RNDIS, Serial, and Mass Storage.

In the Catalog Items View,

USB Function Driver: used to support USB Device driver.

USB Host Support: used to support USB Host controller driver.

To change a USB Device to a USB Host, both the hardware and software need to be modified.

As for the hardware, you can refer to the schematic diagram, it seems that two resistors need to be changed;

Software: First, remove the USB Function driver. This can be done by setting BSP_NOUSBFN=1. Then modify the MISCCR register value, MISCCR [3]SEL_USBPAD:USB1 Host/Device select register. 0=Use USB1 as Device, 1=USE USB1 as Host. That is, change the third bit of MISCCR to 1. This is modified in the initialization function. Add a line of code s2440IOP->MISCCR |= (1<<3);