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© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual
Rev. 01 — 15 August 2005
206
Philips Semiconductors
UM10139
Volume 1
Chapter 14: USB Device Controller
14.7.9 USB Endpoint Interrupt Clear register (USBEpIntClr - 0xE009 0038)
Writing a 1 to this bit clears the bit in the endpoint interrupt status register. Writing 0 will
not have any impact. When the endpoint interrupt is cleared from this register, the
hardware will clear the CDFULL bit in the Device Interrupt Status register. On completion
of this action, the CDFULL bit will be set and the Command Data register will have the
status of the endpoint. Endpoint Interrupt register and CDFULL bit of Device Interrupt
status register are related through clearing of interrupts in USB clock domain. Whenever
software attempts to clear a bit of Endpoint Interrupt register, hardware will clear CDFULL
bit before it starts issuing "Select Endpoint/Clear Interrupt" command (refer to
14.9.11 “Select Endpoint/Clear Interrupt (Command: 0x40 - 0x5F, Data: read 1 byte)” on
page 229
) and sets the same bit when command data is available for reading. Software
will have to wait for CDFULL bit to be set to '1' (whenever it expects data from hardware)
before it can read Command Data register. Each physical endpoint has its own reserved
bit in this register. The bit field definition is the same as the Endpoint Interrupt Status
Register as shown in Table 172. The USBEpIntClr is a write only register.
Software is allowed to issue clear operation on multiple endpoints as well. Let us take an
example:
Assume bits 5 and 10 of Endpoint Interrupt Status register are to be cleared. The software
can issue Clear operation by writing in Endpoint Interrupt Clear register (with
corresponding bit positions set to '1'). Then hardware will do the following:
1. Clears CDFULL bit of Device Interrupt Status register.
Table 188: USB Endpoint Interrupt Enable register (USBEpIntEn - address 0xE009 0034) bit description
Bit
Symbol
Value
Description
Reset value
31:0
See
USBEpIntEn
bit allocation
table above
0
No effect.
0
1
The corresponding bit in the Endpoint Interrupt Status register
(
) transfers its status to the Device Interrupt Status register
(
). Having a bit in the USBEpIntEn set to 1 implies operating
in the slave mode.
Table 189: USB Endpoint Interrupt Clear register (USBEpIntClr - address 0xE009 0038) bit allocation
Reset value: 0x0000 0000
Bit
31
30
29
28
27
26
25
24
Symbol
EP15TX
EP15RX
EP14TX
EP14RX
EP13TX
EP13RX
EP12TX
EP12RX
Bit
23
22
21
20
19
18
17
16
Symbol
EP11TX
EP11RX
EP10TX
EP10RX
EP9TX
EP9RX
EP8TX
EP8RX
Bit
15
14
13
12
11
10
9
8
Symbol
EP7TX
EP7RX
EP6TX
EP6RX
EP5TX
EP5RX
EP4TX
EP4RX
Bit
7
6
5
4
3
2
1
0
Symbol
EP3TX
EP3RX
EP2TX
EP2RX
EP1TX
EP1RX
EP0TX
EP0RX
Table 190: USB Endpoint Interrupt Clear register (USBEpIntClr - address 0xE009 0038) bit description
Bit
Symbol
Value
Description
Reset value
31:0
See
USBEpIntClr
bit allocation
table above
0
No effect.
0
1
Clears the corresponding bit in the Endpoint Interrupt Status register.