Motorola MPC823e - Page 817

Communication Processor Module
MOTOROLA MPC823e REFERENCE MANUAL 16-363
USB
COMMUNICATION
16
PROCESSOR MODULE
16.10.6 USB Commands
You can program the CPM command register (CPCR) with the following commands to
transmit data.
• RST—The reset bit is set by the core and cleared by the communication processor
module and when this command is executed, RST and FLG are cleared within two
general system clocks. The RISC microcontroller reset routine is approximately 60
clocks long, but you can start initializing the communication processor module
immediately after this command is issued. RST is useful when the core wants to reset
the registers and parameters for all the channels as well as the RISC microprocessor
and timer tables. However, this bit does not affect the serial interface or parallel I/O
registers.
• USBCMD—This field contains the USB command.
001 = The STOP TX ENDPOINT command disable the transmission of data on the
selected endpoint. After you issue the command, flush the corresponding
endpoint FIFO. No further transmissions will occur until the RESTART TX
ENDPOINT command is issued.
010 = The RESTART TX ENDPOINT command enables the transmission of data
from the corresponding endpoint on the USB. This command is expected by
the USB controller after a STOP TX ENDPOINT command is issued or after a
transmission error (underrun or timeout) occurs.
000 = Reserved.
011 = Reserved.
100 = Reserved.
101 = Reserved.
110 = Reserved.
111 = Reserved.
• ENDPOINT—This bit is the logical pipe number.
00 = Endpoint 0.
01 = Endpoint 1.
10 = Endpoint 2.
11 = Endpoint 3.
USB COMMAND FORMAT (CPCR)
BIT 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
FIELD RST USBCMD 11110000ENDPOINT RES FLG
RESET 0 0 00000000 0 00
R/W R/W RW/ R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W
ADDR (IMMR & 0xFFFF0000) + 0x9C0