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UM10360_0
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 00.06 — 5 June 2009
474 of 808
1.
Features
•
32-bit counter running from PCLK. Counter can be free-running, or be reset by a
generated interrupt.
•
32-bit compare value.
•
32-bit compare mask. An interrupt is generated when the counter value equals the
compare value, after masking. This allows for combinations not possible with a simple
compare.
2.
Description
The Repetitive Interrupt Timer provides a versatile means of generating interrupts at
specified time intervals, without using a standard timer. It is intended for repeating
interrupts that aren’t related to Operating System interrupts. However, it could be used as
an alternative to the Cortex-M3 System Tick Timer (
) if there are different
system requirements.
3.
Register description
[1]
Reset Value reflects the data stored in used bits only. It does not include content of reserved bits.
3.1 RI Compare Value register (RICOMPVAL - 0x400B 0000)
3.2 RI Mask register (RIMASK - 0x400B 0004)
UM10360
Chapter 22: LPC17xx Repetitive Interrupt Timer (RIT)
Rev. 00.06 — 5 June 2009
User manual
Table 414. Repetitive Interrupt Timer register map
Name
Description
Access
Reset value
Address
RICOMPVAL
Compare register
R/W
0xFFFF FFFF
0x400B 0000
RIMASK
Mask register. This register holds the 32-bit mask
value. A ‘1’ written to any bit will force a compare on
the corresponding bit of the counter and compare
register.
R/W
0x0000 0000
0x400B 0004
RICTRL
Control register.
R/W
0xC
0x400B 0008
RICOUNTER
32-bit counter
R/W
0x0000 0000
0x400B 000C
Table 415. RI Compare Value register (RICOMPVAL - address 0x400B 0000) bit description
Bit
Symbol
Description
Reset value
31:0
RICOMP
Compare register. Holds the compare value which is compared to the
counter.
0xFFFF FFFF
Table 416. RI Compare Value register (RICOMPVAL - address 0x400B 0004) bit description
Bit
Symbol
Description
Reset value
31:0
RIMASK
Mask register. This register holds the 32-bit mask value. A ‘1’ written to any
bit will force a compare on the corresponding bit of the counter and compare
register.
0x0000 0000