OrgApache/incubator-nuttx
OrgApache
/
incubator-nuttx
mirror of https://github.com/apache/incubator-nuttx.git
1
0
Fork 0
Code Issues Releases Wiki Activity

clean up of SPI bit bang logic

This commit is contained in:
Gregory Nutt 2013-07-01 17:49:43 -06:00
parent 5f066efd2d
commit ba19aff54c
1 changed files with 14 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
configs/arduino-due/src/sam_mmcsd.c
View File

@ -77,6 +77,17 @@
#define SPI_CLRMOSI putreg32(1 << 7, SAM_PIOD_CODR) #define SPI_CLRMOSI putreg32(1 << 7, SAM_PIOD_CODR)
#define SPI_GETMISO ((getreg32(SAM_PIOD_PDSR) >> 8) & 1) #define SPI_GETMISO ((getreg32(SAM_PIOD_PDSR) >> 8) & 1)
/* Only mode 0 */
#undef SPI_BITBANG_DISABLEMODE0
#define SPI_BITBANG_DISABLEMODE1 1
#define SPI_BITBANG_DISABLEMODE2 1
#define SPI_BITBANG_DISABLEMODE3 1
/* Only 8-bit data width */
#undef SPI_BITBANG_VARWIDTH
/* SPI_PERBIT_NSEC is the minimum time to transfer one bit. This determines /* SPI_PERBIT_NSEC is the minimum time to transfer one bit. This determines
* the maximum frequency and is also used to calculate delays to achieve * the maximum frequency and is also used to calculate delays to achieve
* other SPI frequencies. * other SPI frequencies.
@ -87,7 +98,9 @@
* I measured a frequency of approximately 305KHz. * I measured a frequency of approximately 305KHz.
* *
* NOTE that there are really only two frequencies possible: hold time=1 * NOTE that there are really only two frequencies possible: hold time=1
* (305KHz) and hold time = 0 (probably around 781KHz) * (305KHz) and hold time = 0 (probably around 781KHz). I believe that
* the code is capable of rates up to around 10MHz, but I think that the
* mere presence of the rate controlling logic slows it down.
*/ */
#define SPI_PERBIT_NSEC 1350 /* Calibrated at 400KHz */ #define SPI_PERBIT_NSEC 1350 /* Calibrated at 400KHz */