PIC18F25J50 MICROCHIP [Microchip Technology], PIC18F25J50 Datasheet - Page 372

• Manufacturer Part Number: PIC18F25J50
• Description: 28/44-Pin, Low-Power, High-Performance USB Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F46J50 FAMILY
22.5
The USB module can generate multiple interrupt condi-
tions. To accommodate all of these interrupt sources,
the module is provided with its own interrupt logic struc-
ture, similar to that of the microcontroller. USB interrupts
are enabled with one set of control registers and
trapped with a separate set of flag registers. All sources
are funneled into a single USB interrupt request, USBIF
(PIR2<4>), in the microcontroller’s interrupt logic.
Figure 22-7
module. There are two layers of interrupt registers in
the USB module. The top level consists of overall USB
FIGURE 22-7:
FIGURE 22-8:
DS39931D-page 372
Differential Data
Note 1:
USB Interrupts
provides the interrupt logic for the USB
The control transfer shown here is only an example showing events that can occur for every transaction. Typical
control transfers will spread across multiple frames.
USB Reset
UEIR (Flag) and UEIE (Enable) Registers
URSTIF
RESET
CRC5EF
CRC5EE
BTOEE
BTSEE
BTOEF
BTSEF
Second Level USB Interrupts
Start-of-Frame (SOF)
PIDEE
PIDEF
CRC16EE
CRC16EF
DFN8EE
USB INTERRUPT LOGIC FUNNEL
DFN8EF
EXAMPLE OF A USB TRANSACTION AND INTERRUPT EVENTS
(USB Error Conditions)
SOFIF
SOF
SETUP
DATA
STATUS
STALLIE
STALLIF
status interrupts. These interrupts are enabled and
flagged in the UIE and UIR registers, respectively. The
second level consists of USB error conditions, which
are enabled and flagged in the UEIR and UEIE
registers. An interrupt condition in any of these areas
triggers a USB Error Interrupt Flag (UERRIF) in the
top level.
Interrupts may be used to trap routine events in a USB
transaction.
events within a USB frame and their corresponding
interrupts.
UERRIF
UERRIE
ACTVIE
URSTIE
ACTVIF
URSTIF
SETUP Token
IDLEIE
OUT Token
IDLEIF
Control Transfer
SOFIE
TRNIE
SOFIF
TRNIF
From Host
From Host
From Host
IN Token
UIR (Flag) and UIE (Enable) Registers
Top Level USB Interrupts
(USB Status Interrupts)
Empty Data
Transaction
From Host
From Host
Figure 22-8
To Host
(1)
Data
Data
 2011 Microchip Technology Inc.
From Host
To Host
To Host
ACK
ACK
ACK
provides some common
SOF
1 ms Frame
USBIF
Transaction
Set TRNIF
Set TRNIF
Set TRNIF
Complete