ST STM32F412 User Manual

USB on-the-go full-speed (OTG_FS) RM0402
1072/1163 RM0402 Rev 6
29.16.2 Host initialization
To initialize the core as host, the application must perform the following steps:
1. Program the HPRTINT in the OTG_GINTMSK register to unmask
2. Program the OTG_HCFG register to select full-speed host
3. Program the PPWR bit in OTG_HPRT to 1. This drives V
BUS
on the USB.
4. Wait for the PCDET interrupt in OTG_HPRT0. This indicates that a device is
connecting to the port.
5. Program the PRST bit in OTG_HPRT to 1. This starts the reset process.
6. Wait at least 10 ms for the reset process to complete.
7. Program the PRST bit in OTG_HPRT to 0.
8. Wait for the PENCHNG interrupt in OTG_HPRT.
9. Read the PSPD bit in OTG_HPRT to get the enumerated speed.
10. Program the HFIR register with a value corresponding to the selected PHY clock 1
11. Program the FSLSPCS field in the OTG_HCFG register following the speed of the
device detected in step 9. If FSLSPCS has been changed a port reset must be
performed.
12. Program the OTG_GRXFSIZ register to select the size of the receive FIFO.
13. Program the OTG_HNPTXFSIZ register to select the size and the start address of the
Non-periodic transmit FIFO for non-periodic transactions.
14. Program the OTG_HPTXFSIZ register to select the size and start address of the
periodic transmit FIFO for periodic transactions.
To communicate with devices, the system software must initialize and enable at least one
channel.
29.16.3 Device initialization
The application must perform the following steps to initialize the core as a device on power-
up or after a mode change from host to device.
1. Program the following fields in the OTG_DCFG register:
– Device speed
– Non-zero-length status OUT handshake
– Periodic Frame Interval
2. Clear the DCTL.SDIS bit. The core issues a connect after this bit is cleared.
3. Program the OTG_GINTMSK register to unmask the following interrupts:
– USB reset
– Enumeration done
– Early suspend
– USB suspend
–SOF
4. Wait for the USBRST interrupt in OTG_GINTSTS. It indicates that a reset has been
detected on the USB that lasts for about 10 ms on receiving this interrupt.
5. Wait for the ENUMDNE interrupt in OTG_GINTSTS. This interrupt indicates the end of
reset on the USB. On receiving this interrupt, the application must read the OTG_DSTS

ST STM32F412 Specifications

General

Brand	ST
Model	STM32F412
Category	Microcontrollers
Language	English