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UM10375
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© NXP B.V. 2011. All rights reserved.
User manual
Rev. 3 — 14 June 2011
28 of 368
NXP Semiconductors
UM10375
Chapter 3: LPC13xx System configuration
3.5.21 SSP1 clock divider register
This register configures the SSP1 peripheral clock SSP1_PCLK. The SSP1_PCLK can be
shut down by setting the DIV bits to 0x0.
3.5.22 Trace clock divider register
This register configures the ARM trace clock. The trace clock can be shut down by setting
the DIV bits to 0x0.
3.5.23 SYSTICK clock divider register
This register configures the SYSTICK peripheral clock. The SYSTICK timer clock can be
shut down by setting the DIV bits to 0x0.
3.5.24 USB clock source select register
This register selects the clock source for the USB usb_clk. The clock source can be either
the USB PLL output or the main clock, and the clock can be further divided by the
USBCLKDIV register (see
) to obtain a 48 MHz clock.
The USBCLKUEN register (see
) must be toggled from LOW to HIGH for
the update to take effect.
Table 28.
SSP1 clock divider register (SSP1CLKDIV, address 0x4004 809C) bit description
Bit
Symbol
Description
Reset
value
7:0
DIV
SSP1_PCLK clock divider values
0: Disable SSP1_PCLK.
1: Divide by 1.
to
255: Divide by 255.
0x00
31:8
-
Reserved
0x00
Table 29.
TRACECLKDIV clock divider register (TRACECLKDIV, address 0x4004 80AC) bit
description
Bit
Symbol
Description
Reset value
7:0
DIV
ARM trace clock divider values.
0: Disable TRACE_CLK.
1: Divide by 1.
to
255: Divide by 255.
0x00
31:8
-
Reserved
0x00
Table 30.
SYSTICK clock divider register (SYSTICKCLKDIV, address 0x4004 80B0) bit
description
Bit
Symbol
Description
Reset value
7:0
DIV
SYSTICK clock divider values.
0: Disable SYSTICK timer clock.
1: Divide by 1.
to
255: Divide by 255.
0x00
31:8
-
Reserved
0x00