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UM10375
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© NXP B.V. 2011. All rights reserved.
User manual
Rev. 3 — 14 June 2011
17 of 368
NXP Semiconductors
UM10375
Chapter 3: LPC13xx System configuration
3.5.2 Peripheral reset control register
This register allows software to reset the SSP0/1 and I2C peripherals. Writing a 0 to the
SSP0/1_RST_N or I2C_RST_N bits resets the SSP0/1 or I2C peripherals. Writing a 1
de-asserts the reset.
Remark:
Before accessing the SSP0/1 and I2C peripherals, write a 1 to this register to
ensure that the reset signals to the SSP0/1 and I2C are de-asserted.
3.5.3 System PLL control register
This register connects and enables the system PLL and configures the PLL multiplier and
divider values. The PLL accepts an input frequency from 10 MHz to 25 MHz from various
clock sources. The input frequency is multiplied up to a high frequency, then divided down
to provide the actual clock used by the CPU, peripherals, and optionally the USB
subsystem. Note that the USB subsystem has its own dedicated PLL. The PLL can
produce a clock up to the maximum allowed for the CPU, which is 72 MHz.
Table 8.
System memory remap register (SYSMEMREMAP, address 0x4004 8000) bit
description
Bit
Symbol
Value
Description
Reset
value
1:0
MAP
System memory remap
10
0x0
Boot Loader Mode. Interrupt vectors are re-mapped to Boot
ROM.
0x1
User RAM Mode. Interrupt vectors are re-mapped to Static
RAM.
0x2
User Flash Mode. Interrupt vectors are not re-mapped and
reside in Flash.
31:2
-
-
Reserved
0x00
Table 9.
Peripheral reset control register (PRESETCTRL, address 0x4004 8004) bit
description
Bit
Symbol
Value
Description
Reset
value
0
SSP0_RST_N
SSP0 reset control
0
0
Reset SSP0.
1
De-assert SSP0 reset.
1
I2C_RST_N
I2C reset control
0
0
Reset I2C.
1
De-asset I2C reset.
2
SSP1_RST_N
SSP1 reset control
0
0
Reset the SSP1.
1
De-assert SSP1 reset.
31:3
-
-
Reserved
0x00