JDP2S01T Datasheet, PDF (33/150 Pages) Toshiba Semiconductor – UHF~VHF Band RF Attenuator Applications

Philips Semiconductors
ISP1362
Single-chip USB OTG controller
communicates with the A-device as long as it wishes. When the B-device finishes
communicating with the A-device, both the devices finally go into the idle state. See
Figure 18 and Figure 19.
11.3 Session Request Protocol (SRP)
As a dual-role device, the ISP1362 can initiate and respond to SRP. The B-device
initiates SRP by data line pulsing followed by V_BUS pulsing. The A-device can detect
either data line pulsing or V_BUS pulsing.
11.3.1 B-device initiating SRP
The ISP1362 can initiate SRP by performing the following steps:
1. Detect initial conditions [read ID_REG, B_SESS_END and SE0_2MS (bits 0,
2 and 9) of the OtgStatus register].
2. Start data line pulsing [set LOC_CONN (bit 4) of OtgControl register to logic 1].
3. Wait for 5 ms to 10 ms.
4. Stop data line pulsing [set LOC_CONN (bit 4) of OtgControl register to logic 0].
5. Start V_BUS pulsing [set CHRG_V_BUS (bit 1) of the OtgControl register to logic 1].
6. Wait for 10 ms to 20 ms.
7. Stop V_BUS pulsing [set CHRG_V_BUS (bit 1) of the OtgControl register to logic 0].
8. Discharge V_BUS for about 30 ms [by using DISCHRG_V_BUS (bit 2) of the
OtgControl register], optional.
The B-device must complete both data line pulsing and V_BUS pulsing within 100 ms.
11.3.2 A-device responding to SRP
The A-device must be able to respond to one of the two SRP events: data line pulsing
or V_BUS pulsing. The ISP1362 allows you to choose which SRP to support and has a
mechanism to disable or enable the SRP detection. This is useful for some
applications under certain cases. For example, if the A-device battery is low, it may
not want to turn on its V_BUS by detecting SRP. In this case, it may choose to disable
the SRP detection function.
When the data line SRP detection is used, the ISP1362 can detect either the
DP pulsing or the DM pulsing. This means a peripheral-only device can initiate data
line pulsing SRP through DP (full-speed) or DM (low-speed). A dual-role device will
always initiate data line pulsing SRP through DP because it is a full-speed device.
• Steps to enable the SRP detection by V_BUS pulsing:
– Set A_SEL_SRP (bit 9) of the OtgControl register to logic 0.
– Set A_SRP_DET_EN (bit 10) of the OtgControl register to logic 1.
• Steps to enable the SRP detection by data line pulsing:
– Set A_SEL_SRP (bit 9) of the OtgControl register to logic 1.
– Set A_SRP_DET_EN (bit 10) of the OtgControl register to logic 1.
• Steps to disable the SRP detection:
– Set A_SRP_DET_EN (bit 10) of the OtgControl register to logic 0.
9397 750 12337
Product data
Rev. 03 — 06 January 2004
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
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