Hi Peter,
It seems it's impossible to use USB1 without 12/16/24M external clock input. The USBHS controller interfaces to the processor's core. The on-chip UTMI PHY supports high-speed(HS) applications, as well as full-speed and low-speed. This PHY can only have 480M clock from USBPHYPLLCLK. And this PLL's clock source can only be the external clock.
Regards,
Jing
HI
1) I think that you need to select the controller type in usb_host_config.h, whereby the EHCI - presumably HS controller is enabled by default. Since I don't use SDK I don't know full details but it is probably in the doc somewhere:
/* Host Controller Enable */
/*!
* @brief host khci instance count, meantime it indicates khci enable or disable.
* - if 0, host khci driver is disable.
* - if greater than 0, host khci driver is enable.
*/
#define USB_HOST_CONFIG_KHCI (0U)
/*!
* @brief host ehci instance count, meantime it indicates ehci enable or disable.
* - if 0, host ehci driver is disable.
* - if greater than 0, host ehci driver is enable.
*/
#define USB_HOST_CONFIG_EHCI (1U)
/*!
* @brief host ohci instance count, meantime it indicates ohci enable or disable.
* - if 0, host ohci driver is disable.
* - if greater than 0, host ohci driver is enable.
*/
#define USB_HOST_CONFIG_OHCI (0U)
2. The HS USB PHY needs a 480 MHz clock for its operation (for its internal PLL), irrespective of whether it finally operates in LS/FS or HS mode (which depends on the device attached) so if you don't one of the crystal speeds that support this you can't use the HS USB controller, but you can still use the FS USB controller.
3. In device mode the FS USB also can operate in crystal-less mode and so is not dependent on the clock you use.
If you have a 50MHz crystal or oscillator you can use it for USB device or host with settings:
PLL input divide 5 (to give 10MHz input), 24x multiply to give 240MHz PLL output (120MHz core), select MCGPLLCLK as source to USB and SIM_CLKDIV2 to 0x00000009 (divide 5 with fraction set).
In the uTasker project this is highly automated so I just chose
K66,
not USB_HS_INTERFACE
#define CRYSTAL_FREQUENCY 50000000
#define CLOCK_DIV 5
#define CLOCK_MUL 24
and then its simulator conformed all operation in device and host modes and I could read the values that were set.
Regards
Mark
[uTasker project developer for Kinetis and i.MX RT]
Hi Peter,
It seems it's impossible to use USB1 without 12/16/24M external clock input. The USBHS controller interfaces to the processor's core. The on-chip UTMI PHY supports high-speed(HS) applications, as well as full-speed and low-speed. This PHY can only have 480M clock from USBPHYPLLCLK. And this PLL's clock source can only be the external clock.
Regards,
Jing
Hi Peter,
Before I would look at your questions 1. and 2. I would like to ask you why the choice of the 50MHz oscillator and not the values specified in the RM (Point 3.)?
AFAIK, you must have a 48MHz clock going into the USB module, which means that you need a base clock that can be divided/multiplied to 48MHz within the confines of the circuitry within the Kinetis. I don't think this is possible with a 50MHz clock. This should be the first issue that you need to address: get a 48MHz clock out at "USB FS clock" and see where you need to go from there.
There is no single point of reference explaining Kinetis clocking and, while the clock tool in MCUXpresso is helpful, there's nothing that allows you to enter in your requirements and spit out a clock_config.c/.h file without you spending a lot of time learning about how clocking works and how to specify the various outputs to get exactly what you need. If you look over the Community over the past few months, you'll see a lot of the hair pulling I went through learning it well enough to be able to specify the full speed operation of the MK22FN1M0Axxx12 used in my product as well as get the correct clock specification for the different hardware interfaces (including USB) that I am using in my product.
Here's the final result of that work:
Good luck!
myke
