RM0390 Rev 4 1203/1328
RM0390 USB on-the-go full-speed/high-speed (OTG_FS/OTG_HS)
1264
31.16 OTG_FS/OTG_HS programming model
31.16.1 Core initialization
The application must perform the core initialization sequence. If the cable is connected
during power-up, the current mode of operation bit in the OTG_GINTSTS (CMOD bit in
OTG_GINTSTS) reflects the mode. The OTG_FS/OTG_HS controller enters host mode
when an “A” plug is connected or device mode when a “B” plug is connected.
This section explains the initialization of the OTG_FS/OTG_HS controller after power-on.
The application must follow the initialization sequence irrespective of host or device mode
operation. All core global registers are initialized according to the core’s configuration:
1. Program the following fields in the OTG_GAHBCFG register:
– Global interrupt mask bit GINTMSK = 1
– Rx FIFO non-empty (RXFLVL bit in OTG_GINTSTS)
– Periodic Tx FIFO empty level
2. Program the following fields in the OTG_GUSBCFG register:
– HNP capable bit
– SRP capable bit
– OTG_FS/OTG_HS timeout calibration field
– USB turnaround time field
3. The software must unmask the following bits in the OTG_GINTMSK register:
OTG interrupt mask
Mode mismatch interrupt mask
4. The software can read the CMOD bit in OTG_GINTSTS to determine whether the
OTG_FS/OTG_HS controller is operating in host or device mode.
31.16.2 Host initialization
To initialize the core as host, the application must perform the following steps:
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