ISP1161A

The ISP1161A is a single-chip Universal Serial Bus (USB) Host Controller (HC) and Device Controller (DC). The Host Controller portion of the ISP1161A complies with Universal Serial Bus Specification Rev. 2.0, supporting data rates at full-speed (12 Mbit/s) and low-speed (1.5 Mbit/s). The Device Controller portion of the ISP1161A also complies with Universal Serial Bus Specification Rev. 2.0, supporting data rates at full-speed (12 Mbit/s). These two USB controllers, the HC and the DC, share the same microprocessor bus interface. They have the same data bus, but different I/O locations. They also have separate interrupt request output pins, separate DMA channels that include separate DMA request output pins and DMA acknowledge input pins. This makes it possible for a microprocessor to control both the USB HC and the USB DC at the same time.

ISP1161A provides two downstream ports for the USB HC and one upstream port for the USB DC. Each downstream port has an overcurrent (OC) detection input pin and power supply switching control output pin. The upstream port has a V_BUS detection input pin. ISP1161A also provides separate wake-up input pins and suspended status output pins for the USB HC and the USB DC, respectively. This makes power management flexible. The downstream ports for the HC can be connected with any USB compliant devices and hubs that have USB upstream ports. The upstream port  for the DC can be connected to any USB compliant USB host and USB hubs that have USB downstream ports.

The HC is adapted from the Open Host Controller Interface Specification for USB Release 1.0a, referred to as OHCI in the rest of this document.

The DC is compliant with most USB device class specifications such as Imaging Class, Mass Storage Devices, Communication Devices, Printing Devices and Human Interface Devices.

ISP1161A is well suited for embedded systems and portable devices that require a USB host only, a USB device only, or a combination of a configurable USB host and USB device. ISP1161A brings high flexibility to the systems that have it built-in. For example, a system that uses an ISP1161A allows it not only to be connected to a PC or USB hub with a USB downstream port, but also to be connected to a device that has a USB upstream port such as a USB printer, USB camera, USB keyboard or a USB mouse. Therefore, the ISP1161A enables peer-to-peer connectivity between embedded systems. An interesting application example is to connect an ISP1161A HC with an ISP1161A DC.

Consider an example of an ISP1161A being used in a Digital Still Camera (DSC) design. Figure 1 shows an ISP1161A being used as a USB DC. Figure 2 shows an ISP1161A being used as a USB HC. Figure 3 shows an ISP1161A being used as a USB HC and a USB DC at the same time.