diff options
Diffstat (limited to 'nuttx/configs/sam4e-ek/README.txt')
| -rw-r--r-- | nuttx/configs/sam4e-ek/README.txt | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/nuttx/configs/sam4e-ek/README.txt b/nuttx/configs/sam4e-ek/README.txt index 720566adf..25438c6ef 100644 --- a/nuttx/configs/sam4e-ek/README.txt +++ b/nuttx/configs/sam4e-ek/README.txt @@ -660,7 +660,8 @@ USB Full-Speed Device b. If you change the value CONFIG_SYSTEM_USBMSC_DEVPATH1, then you can export other file systems: - "/dev/mmcsd0" would export the HSMCI SD slot + "/dev/mmcsd0" would export the HSMCI SD slot (not currently available, + see the "HSMCI" section). "/dev/ram0" could even be used to export a RAM disk. But you would first have to use mkrd to create the RAM disk and mkfatfs to put @@ -781,6 +782,14 @@ HSMCI The SD card contents will then be available under /mnt/sdcard. + NOTES: + + 1. DMA is not currently functional and without DMA, there may not be + reliable data transfers at high speeds due to data overrun problems. + The current HSMCI driver supports DMA via the DMAC. However, the data + sheet only discusses PDC-based HSMCI DMA (although there is a DMA + channel interface definition for HSMCI). + Touchscreen =========== @@ -1171,7 +1180,12 @@ Configurations instructions provided above in the paragraph entitled "HSMCI." STATUS: - 2014-3-21: The HSMCI SD card slot has not yet been tested. + 2014-3-24: DMA is not currently functional and without DMA, there + may not be reliable data transfers at high speeds due + to data overrun problems. The current HSMCI driver + supports DMA via the DMAC. However, the data sheet + only discusses PDC-based HSMCI DMA (although there is + a DMA channel interface definition for HSMCI). usbnsh: |