TUSB3200 datasheet(21/93 Pages) TI

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2–5

2.2.2.3.1 Application Code

Application firmware is stored as a binary image of the code. The binary image is mapped to the MCU program

memory space starting at address zero and is stored in the EEPROM as a continuous linear block starting after the

header information. A utility program is available that converts a file in Intel hexidecimal format to a binary image data

file and appends it to the header.

2.2.2.3.2 USB Device Information

The USB device information is comprised of the vendor ID and product ID. Optionally, a manufacturer string and

product string can be included. The boot loader uses this information during enumeration to identify the USB

peripheral device. Table 2-2 shows the format and information contained in the

USB Device Information Section.

Table 2–2. USB Device Information

OFFSET

TYPE

SIZE

CONTENTS

REMARK

H+1

Vendor ID

Vendor ID code

H+3

Product ID

Product ID code

H+5

M Offset

Pointer to manufacture string

String is optional

H+6

P Offset

Pointer to product string

String is optional

H+M Offset

Manufacture string

Null terminated

H+P Offset

Product string

Null terminated

2.2.2.4 EEPROM Device Type

The TUSB3200 boot loader program supports several different types of serial EEPROM devices. The boot loader

program will automatically identify the EEPROM type from the header information and use the correct serial interface

protocol accordingly. The boot loader program uses an I2C slave device address of A0h for the serial EEPROM

device.

These EEPPROM devices require an I2C device address in addition to a two byte data word address. These devices

require the full 7-bit I2C device address. Depending on the memory size of the EEPROM device being used, the most

significant three or four bits of the two byte data word address are don’t care bits. The EEPROM types supported are:

24C32 and 24C64

All of these EEPROM devices can be used for storing and loading application code. However most applications will

use devices which are capable of storing up to 8K bytes of program code.

2.2.3

USB Enumeration

USB enumeration is accomplished by interaction between the host PC software and the TUSB3200 code. After

power-on reset the boot loader code first reads the information from the EEPROM, then runs the application code.

The application code connects the TUSB3200 to the USB. During the enumeration, the application code identifies

the device as an application specific device and the host loads the appropriate host driver(s). The boot loader and

application code both use the CONT, SDW and FRSTE bits to control the enumeration process. The function connect

(CONT) bit is set to a 1 by the MCU to connect the TUSB3200 device to the USB. When this bit is set to a 1, the USB

data plus pullup resistor (PUR) output signal is enabled, which will connect the pullup on the PCB to the TUSB3200

3.3-V digital supply voltage. When this bit is cleared to a 0, the PUR output is in the 3-state mode. This bit is not

affected by a USB reset. The shadow the boot ROM (SDW) bit is set to a 1 by the MCU to switch the MCU memory

configuration from boot loader mode to normal operating mode. The function reset enable (FRSTE) bit is set to a 1

by the MCU to enable the USB reset to reset all internal logic including the MCU. However, the shadow the ROM

(SDW) and the USB function connect (CONT) bits will not be reset. When this bit is set, the reset output (RSTO) signal

from the TUSB3200 device will also be active when a USB reset occurs. This bit is not affected by USB reset.

2.2.4

USB Reset

The TUSB3200 can detect a USB reset condition. When the reset occurs, the TUSB3200 responds by setting the

function reset (RSTR) bit in the USB status register (USBSTA). If the corresponding function reset bit in the USB

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