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| author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2013-03-28 13:35:50 +0000 |
|---|---|---|
| committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2013-03-28 13:35:50 +0000 |
| commit | c942ffd840bb16140db80f04873c875830c31f67 (patch) | |
| tree | 9b2cdbd9a04deb63e28d9e443c603d0bc1649410 /nuttx | |
| parent | a15c952cd525e220d428fbd88ce7de7fc4efec59 (diff) | |
| download | px4-nuttx-c942ffd840bb16140db80f04873c875830c31f67.tar.gz px4-nuttx-c942ffd840bb16140db80f04873c875830c31f67.tar.bz2 px4-nuttx-c942ffd840bb16140db80f04873c875830c31f67.zip | |
Fix Open1788 EMC clocking
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5796 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx')
| -rw-r--r-- | nuttx/configs/open1788/include/board.h | 9 | ||||
| -rw-r--r-- | nuttx/configs/open1788/src/lpc17_sdraminitialize.c | 15 |
2 files changed, 15 insertions, 9 deletions
diff --git a/nuttx/configs/open1788/include/board.h b/nuttx/configs/open1788/include/board.h index 369d08eba..bf9918199 100644 --- a/nuttx/configs/open1788/include/board.h +++ b/nuttx/configs/open1788/include/board.h @@ -123,11 +123,13 @@ #ifdef CONFIG_LPC17_EMC /* EMC clock selection. * - * The EMC uses the CPU clock undivided. + * The EMC clock should not be driven above 80MHz. As a result the EMC + * uses the CPU clock divided by two. */ -# define BOARD_EMCCLKSEL_VALUE SYSCON_EMCCLKSEL_CCLK_DIV1 -# define LPC17_EMCCLK LPC17_CCLK +# define BOARD_EMCCLKSEL_DIVIDER 2 +# define BOARD_EMCCLKSEL_VALUE SYSCON_EMCCLKSEL_CCLK_DIV2 +# define LPC17_EMCCLK (LPC17_CCLK / BOARD_EMCCLKSEL_DIVIDER) #endif #if defined(CONFIG_LPC17_USBHOST) || (CONFIG_LPC17_USBDEV) @@ -136,6 +138,7 @@ * USBCLK = PLL1CLK = (SYSCLK * 4) = 48MHz */ +# define BOARD_USBCLKSEL_DIVIDER 1 # define BOARD_USBCLKSEL_VALUE (SYSCON_USBCLKSEL_USBDIV_DIV1 | \ SYSCON_USBCLKSEL_USBSEL_PLL1) #endif diff --git a/nuttx/configs/open1788/src/lpc17_sdraminitialize.c b/nuttx/configs/open1788/src/lpc17_sdraminitialize.c index e18643f20..10196b18c 100644 --- a/nuttx/configs/open1788/src/lpc17_sdraminitialize.c +++ b/nuttx/configs/open1788/src/lpc17_sdraminitialize.c @@ -62,15 +62,18 @@ * * For example: * LPC17_CCLCK = 120,000,000 - * EMCCLKSEL -> use LPC17_CCLK undivided - * LPC17_EMCCLK = 120,000,000 - * LPC17_EMCCLK_MHZ = 120 (rounded) - * EMC_NSPERCLK = 8 (rounded) + * EMCCLKSEL -> LPC17_CCLK divided by 2 + * LPC17_EMCCLK = 60,000,000 + * LPC17_EMCCLK_MHZ = 60 (Rounded to an integer) + * EMC_NSPERCLK = 16.667 (Represented with 4 bits of fraction, 267) + * + * EMC_NS2CLK(63) = ((63 << 4) + 266) / 267 = 4 (actual 3.78) + * EMC_NS2CLK(20) = ((20 << 4) + 266) / 267 = 2 (actual 1.20) */ #define LPC17_EMCCLK_MHZ ((LPC17_EMCCLK + 500000) / 1000000) -#define EMC_NSPERCLK ((1000 + (LPC17_EMCCLK_MHZ >> 1)) / LPC17_EMCCLK_MHZ) -#define EMC_NS2CLK(ns) ((ns + (EMC_NSPERCLK - 1)) / EMC_NSPERCLK) +#define EMC_NSPERCLK_B4 (((1000 << 4) + (LPC17_EMCCLK_MHZ >> 1)) / LPC17_EMCCLK_MHZ) +#define EMC_NS2CLK(ns) (((ns << 4) + (EMC_NSPERCLK_B4 - 1)) / EMC_NSPERCLK_B4) #define MDKCFG_RASCAS0VAL 0x00000303 /* Set up for 32-bit SDRAM at CS0 */ |