Datasheet

TUSB3410 Bootcode Flow

SLLS519H—January 2010TUSB3410, TUSB3410I

11.8.7 Internal ROM Memory Read

The bootcode returns the byte of the specified address within the boot ROM. That is, the binary code of the

bootcode.

bmRequestType USB_REQ_TYPE_DEVICE |

USB_REQ_TYPE_VENDOR |

USB_REQ_TYPE_OUT

01000000b

bRequest BTC_INTERNAL_ROM_MEMORY_READ 0x94

wValue None 0x0000

wIndex Data address 0xNNNN (From 0x0000 to 0xFFFF)

wLength 1 byte 0x0001

Data Byte in the specified address 0xNN

11.9 Bootcode Programming Consideration

11.9.1 USB Requests

For each USB request, the bootcode follows the steps below to ensure proper operation of the hardware.

1. Determine the direction of the request by checking the MSB of the bmRequestType field and set the DIR

bit within the USBCTL register accordingly.

2. Decode the command

3. If another setup is pending, then return. Otherwise, serve the request.

4. Check again, if another setup is pending then go to step 2.

5. Clear the interrupt source and then the VECINT register.

6. Exit the interrupt routine.

11.9.1.1 USB Request Transfers

The USB request consist of three types of transfers. They are control-read-with-data-stage, control-write-

without-data-stage, and control-write-with-data-stage transfer. In each transfer, arrows indicate interrupts

generated after receiving the setup packet, in or out token.

Figure 11−1 and Figure 11−2 show the USB data flow and how the hardware and firmware respond to the USB

requests. Table 11−9 and Table 11−10 lists the bootcode reposes to the standard USB requests.