DR
AFT
DR
AFT
DRAFT
DR
D
RAFT
DRAFT
DRA
FT DRAF
D
RAFT DRAFT DRAFT DRAFT DRAFT D
DRAFT
D
RAFT DRA
FT DRAFT DRAFT DRAFT DRA
UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
44 of 571
NXP Semiconductors
UM10316
Chapter 3: LPC29xx Clock Generation Unit (CGU)
[1]
At reset release, the JTAGSEL pin is sampled. If it is LOW (ARM debug), the crystal oscillator (XO50M) will
be selected as source for BASE_SYS_CLK.
5.13 Output-clock status register for CGU1 clocks
There is one status register for each CGU1 output clock generated. All output generators
have the same register bits.
Table 26.
XX_CLK_CONF register bit description (XX = SYS (address 0xFFFF 8070), IVNSS
(address 0xFFFF 8080), MSCSS (address 0xFFFF 8088), UART (address 0xFFFF
8098), SPI (address 0xFFFF 80A0), TMR (address 0xFFFF 80A8), ADC (address
0xFFFF 80B0))
* = reset value
Bit
Symbol
Access
Value
Description
31 to 24 CLK_SEL
R/W
selected source clock
00h*
LP_OSC
01h
Crystal oscillator
02h
PLL
03h
PLL +120
0
04h
PLL +240
0
05h
FDIV0
06h
FDIV1
07h
FDIV2
08h
FDIV3
09h
FDIV4
0Ah
FDIV5
0Bh
FDIV6
23 to 12 reserved
R
-
Reserved
11
AUTOBLOK
W
-
Enables auto-blocking of clock when
programming changes
10 to 5
reserved
R
-
Reserved; do not modify. Read as logic 0, write
as logic 0
4 to 2
IDIV
R/W
000*
Integer divide value
1
reserved
R/W
0*
Reserved; do not modify. Read as logic 0, write
as logic 0
0
PD
R/W
0*
Power-down clock slice
Table 27.
XX_CLK_STATUS register bit description (XX = USB_CLK (address 0xFFFF
B02C), USB_I2C (address 0xFFFF B034), OUT_CLK (address 0xFFFF B03C))
* = reset value
Bit
Symbol
Access
Value
Description
31 to 5
reserved
R
-
Reserved
4 to 2
IDIV
R
000*
Integer divide value
1
RTX
R
0*
Clock-disable polarity
0
PD
R
0*
Power-down clock slice