MC68HC908LD64 Datasheet, PDF (193/362 Pages) Freescale Semiconductor, Inc – Microcontrollers

Universal Serial Bus Module (USB)
Overview
For the embedded device sub-module, three types of USB data transfers
are supported: control, interrupt, and bulk (transmit only). Endpoint 0 of
the embedded device sub-module functions as a receive/transmit
control endpoint. Endpoints 1 and 2 of the embedded device sub-module
can function as interrupt or bulk, but only in the transmit direction.
The block diagram of the USB module is shown Figure 14-2. The USB
module manages communications between the host and the USB
function. The module is partitioned into eight functional blocks. These
blocks consist of a dual function transceiver, the hub repeater function,
the serial interface engine (SIE), the frame counter logic, the hub control
logic, the embedded device control logic, and the endpoint registers.
CPU BUS
EMBEDDED DEVICE
CONTROL LOGIC
ENDPOINT 0
(CONTROL ENDPOINT)
8-BYTE TRANSMIT BUFFER
8-BYTE RECEIVE BUFFER
ENDPOINT 1/2
(INTERRUPT/BULK ENDPOINT)
8-BYTE TRANSMIT BUFFER
REGISTERS
HUB
CONTROL LOGIC
ENDPOINT 0
(CONTROL ENDPOINT)
8-BYTE TRANSMIT BUFFER
8-BYTE RECEIVE BUFFER
ENDPOINT 1
(INTERRUPT ENDPOINT)
8-BYTE TRANSMIT BUFFER
12 MHz
OSCOUT
FROM OSC
FRAME
COUNTER
SERIAL
INTERFACE ENGINE
HUB REPEATER
TRANSCEIVER
TRANSCEIVER
48MHz _CLOCK
DOUBLER
24 MHz
OSCXCLK
FROM OSC
D4+ D4– D3+ D3– D2+ D2– D1+ D1–
DOWNSTREAM PORTS
D0+ D0–
ROOT PORT
Figure 14-2. USB Module Block Diagram
MC68HC908LD64 — Rev. 3.0
Freescale Semiconductor
Universal Serial Bus Module (USB)
Data Sheet
193