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Diffstat (limited to 'nuttx/configs/stm3240g-eval/README.txt')
| -rwxr-xr-x | nuttx/configs/stm3240g-eval/README.txt | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/nuttx/configs/stm3240g-eval/README.txt b/nuttx/configs/stm3240g-eval/README.txt index ef26c0088..e4902947e 100755 --- a/nuttx/configs/stm3240g-eval/README.txt +++ b/nuttx/configs/stm3240g-eval/README.txt @@ -720,9 +720,23 @@ Where <subdir> is one of the following: configuration. 2. RS-232 is disabled, but Telnet is still available for use as a console. + Since RS-232 and SDIO use the same pins (one controlled by JP22), RS232 + and SDIO cannot be used concurrently. 3. This configuration requires that jumper JP22 be set to enable SDIO operation. + 4. In order to use SDIO without overruns, DMA must be used. The STM32 F4 + has 192Kb of SRAM in two banks: 112Kb of "system" SRAM located at + 0x2000:0000 and 64Kb of "TCM" SRAM located at 0x1000:0000. It appears + that you cannot perform DMA from TCM SRAM. The work around that I have now + is simply to omit the 64Kb of TCM SRAM from the heap so that all memory is + allocated from System SRAM. This is done by setting: + + CONFIG_MM_REGIONS=1 + + Then DMA works fine. The downside is, of course, is that we lose 64Kb + of precious SRAM. + ostest: ------ This configuration directory, performs a simple OS test using |