C541U_99 Datasheet, PDF (79/192 Pages) Siemens Semiconductor Group – 8-BIT CMOS MICROCONTROLLER

On-Chip Peripheral Components
C541U
6.4 USB Module
The USB module in the C541U handles all transactions between the serial USB bus and the internal
(parallel) bus of the microcontroller. The USB module includes several units which are required to
support data handling with the USB bus : the on-chip USB bus transceiver, the USB memory with
two pages of 128 bytes each, the memory management unit (MMU) for USB and CPU memory
access control, the UDC device core for USB protocol handling, the microcontroller interface with
the USB specific special function registers and the interrupt control logic. A clock generation unit
provides the clock signal for the USB module for full speed and low speed USB operation. The
following sections describe the full speed operation, while the low speed operation is described
specifically in section 6.4.8. Figure 6-18 shows the block diagram of the functional units of the USB
module with their interfaces.
XTAL1 XTAL2
Pin Pin
Osc.
12 MHz
x4
PLL
48 MHz
2
6 MHz
USB Bus
D+ D-
Pin Pin
Page 1 ^7FH
7FH _{Page 0}
Transceiver
(On-chip)
USB
Memory
(128 x 8)
00 _H
00H
USB
Module
USB
Device
Core
(UDC)
MCU
Data
Data
Interface
Address
11
MMU
SFR
USB Memory
Addr.
Control Management Control
Internal
Bus
Figure 6-18
USB Module Block Diagram
Interrupt Generation
MCB03380
Semiconductor Group
6-34
1999-04-01