UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 402 o f 792
NXP Semiconductors UM10237
Chapter 15: LPC24XX USB OTG controller
2. Free running mode: an interrupt is generated at the end of TIMEOUT_CNT (see Section 15–7.7 “OTG Timer Register (OTGTmr - 0xFFE0C114)), the TMR bit is set, and the timer value is reloaded into the counter. The timer is not disabled in this mode.
Table 365. OTG Status Control register (OTGStCtrl - address 0xFFE0 C110) bit description
Bit Symbol Description Reset
Value
1:0 PORT_FUNC Controls the function of ports U1 and U2. Bit 0 is set or
cleared by hardware when B_HNP_TRACK or
A_HNP_TRACK is set and HNP succeeds. See
Section 15–8.
-
3:2 TMR_SCALE Timer scale selection. This field determines the duration
of each timer count.
00: 10 μs (100 KHz)
01: 100 μs (10 KHz)
10: 1000 μs (1 KHz)
11: R eser ved
0x0
4 TMR_MODE Timer mode selection.
0: monoshot
1: free running
0
5 TMR_EN Timer enable. When set, TMR_CNT increments. When
cleared, TMR_CNT is reset to 0. 0
6 TMR_RST Timer reset. Writing one to this bit resets TMR_CNT to 0.
This provides a single bit control for the software to
restart the timer when the timer is enabled.
0
7 - Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
NA
8 B_HNP_TRACK Enable HNP tracking for B-device (peripheral), see
Section 15–8. Hardware clears this bit when
HNP_SUCCESS or HNP_FAILURE is set.
0
9 A_HNP_TRACK Enable HNP tracking for A-device (host), see
Section 15–8. Hardware clears this bit when
HNP_SUCCESS or HNP_FAILURE is set.
0
10 PU_REMOVED When the B-device changes its role from peripheral to
host, software sets this bit when it removes the D+
pull-up, see Section 15–8. Hardware clears this bit when
HNP_SUCCESS or HNP_FAILURE is set.
0
15:11 - Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
NA
31:16 TMR_CNT Current timer count value. 0x0