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| author | Gregory Nutt <gnutt@nuttx.org> | 2013-09-19 16:10:46 -0600 |
|---|---|---|
| committer | Gregory Nutt <gnutt@nuttx.org> | 2013-09-19 16:10:46 -0600 |
| commit | bfcf82862ab67196f91f5f6138c20111503b55d1 (patch) | |
| tree | 17802971a1ec4fee51295b313c529881ad478a25 | |
| parent | 51355efa04f319b4691ad71409ce7304bd1ff685 (diff) | |
| download | nuttx-bfcf82862ab67196f91f5f6138c20111503b55d1.tar.gz nuttx-bfcf82862ab67196f91f5f6138c20111503b55d1.tar.bz2 nuttx-bfcf82862ab67196f91f5f6138c20111503b55d1.zip | |
SAMA5 OHCI: When UPLL drives OHCI the logically correct divider of 10 does not work; But a divider of 5 does. Why?
| -rw-r--r-- | nuttx/ChangeLog | 3 | ||||
| -rw-r--r-- | nuttx/arch/arm/src/sama5/sam_clockconfig.c | 9 | ||||
| -rw-r--r-- | nuttx/configs/sama5d3x-ek/include/board_384mhz.h | 6 |
3 files changed, 16 insertions, 2 deletions
diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog index e555daa5f..a30e19580 100644 --- a/nuttx/ChangeLog +++ b/nuttx/ChangeLog @@ -5594,4 +5594,7 @@ Correct some inconsistencies in the way that USB configuration settings are used. This caused compilation errors in SAMA5 OHCI when USB debug was ON but USB host tracing was off (2013-9-19). + * nuttx/arch/arm/src/sama5/sam_clockconfig.c: When 480MHz UPLL + is used to drive OHCI, it should have a divider of 10. However, + that does not work. A divider of 5 does. Why? (2013-9-19). diff --git a/nuttx/arch/arm/src/sama5/sam_clockconfig.c b/nuttx/arch/arm/src/sama5/sam_clockconfig.c index a8c0613ef..fd1162164 100644 --- a/nuttx/arch/arm/src/sama5/sam_clockconfig.c +++ b/nuttx/arch/arm/src/sama5/sam_clockconfig.c @@ -397,9 +397,16 @@ static inline void sam_usbclockconfig(void) /* 7) Program the OHCI clocks (UHP48M and UHP12M) with USBDIV field in * PMC_USB register. USBDIV must be 9 (division by 10) if UPLLCK is * selected. + * + * REVISIT: The divisor of 10 produces a rate that is too high. Division + * by 5, however, seems to work just fine. No idea why? */ - regval |= PMC_USB_USBDIV(9); +#if 1 /* REVISIT */ + regval |= PMC_USB_USBDIV(4); /* Division by 5 */ +#else + regval |= PMC_USB_USBDIV(9); /* Division by 10 */ +#endif putreg32(regval, SAM_PMC_USB); #else /* BOARD_USE_UPLL */ diff --git a/nuttx/configs/sama5d3x-ek/include/board_384mhz.h b/nuttx/configs/sama5d3x-ek/include/board_384mhz.h index e52e76e24..02815c1eb 100644 --- a/nuttx/configs/sama5d3x-ek/include/board_384mhz.h +++ b/nuttx/configs/sama5d3x-ek/include/board_384mhz.h @@ -136,7 +136,11 @@ # undef BOARD_USE_UPLL /* Use PLLA as source clock */ # define BOARD_OHCI_INPUT PMC_USB_USBS_PLLA /* Input is PLLACK */ -# define BOARD_OHCI_DIVIDER (7) /* Divided by 8 */ +# if 1 /* REVISIT */ +# define BOARD_OHCI_DIVIDER (7) /* Divided by 8 */ +# else +# define BOARD_OHCI_DIVIDER (15) /* Divided by 16 */ +# endif #endif /* Resulting frequencies */ |