AT89C5131A Ver la hoja de datos (PDF) - Atmel Corporation

Número de pieza

componentes Descripción

Fabricante

AT89C5131A

USB Microcontrollers

Atmel Corporation 

Physical Layer

48 MHz Frequency

Auto-Configuration

The USB norm specifies all the transfers over the USB line. The USB specification also includes

several CLASS and SUB-CLASS specifications. These stand-alone documents are used by the

manufacturer to implement a USB link between a PC and a device supporting the In System

Programming. Mostly, the USB specification is implemented by hardware (automatic reply,

handshakes, timings, ...) and the USB Classes and SubClasses are implemented by software at

a data level.

Figure 5. USB Bus Topography

Downstream Transfer: OUT

PC Driver

PC Application

PC (Host)

Upstream Transfer: IN

Device driver/API

Firmware

USB Line

Application (Device)

The USB is used to transmit information that has the following configuration:

• USB DFU using the Default Control Endpoint only (endpoint 0) with a 32 bytes length.

• 48 MHz for USB controller: USB clock configuration performed by the bootloader

The bootloader includes a function which will automatically setup the PLL frequency (48MHz)

versus the different XTAL configuration used on the application.

The table below shows the allowed frequencies compatible with the USB bootloader

48 MHz auto-generation.

6 MHz

X1 or X2

Clock

OK

Modes

8 MHz 12 MHz 16 MHz 20 MHz 24 MHz 32 MHz 40 MHz 48 MHz

OK

OK

OK

OK

OK

OK

OK

OK

10 AT89C5131A USB Bootloader

4287E–USB–04/08

Share Link: