Posted on May 17, 2011 at 13:05Hello,
Could somebody confirm or explain where I am wrong with the following problem on a STM32F103ZET6 ?
1 – Can we only write once to the FIFO of the SDIO when DPSM is enabled? And Does the DPSM have to be enabled to write to the FIFO?
2 – Does this problem explain why we can only transfer data with 1 byte block (see errata section 2.13 Limited multibyte support with SDIO cards)
/* SDIO configuration */
SDIO_InitStructure.SDIO_ClockDiv = (UI8)0x01;
SDIO_InitStructure.SDIO_ClockEdge = SDIO_ClockEdge_Rising;
SDIO_InitStructure.SDIO_ClockBypass = SDIO_ClockBypass_Disable;
SDIO_InitStructure.SDIO_ClockPowerSave = SDIO_ClockPowerSave_Disable;
SDIO_InitStructure.SDIO_BusWide = SDIO_BusWide_4b;
SDIO_InitStructure.SDIO_HardwareFlowControl = SDIO_HardwareFlowControl_Disable;
SDIO_Init(&SDIO_InitStructure);
/* “FIFO� configuration with DPSM disabled */
SDIO_DataInitStructure.SDIO_DataTimeOut = SD_DATATIMEOUT;
SDIO_DataInitStructure.SDIO_DataLength = 32;
SDIO_DataInitStructure.SDIO_DataBlockSize = SDIO_DataBlockSize_32b;
SDIO_DataInitStructure.SDIO_TransferDir = SDIO_TransferDir_ToCard;
SDIO_DataInitStructure.SDIO_TransferMode = SDIO_TransferMode_Block;
SDIO_DataInitStructure.SDIO_DPSM = SDIO_DPSM_Disable;
SDIO_DataConfig(&SDIO_DataInitStructure);
/* try to write data in the FIFO */
SDIO_WriteData(0x00000001);
SDIO_WriteData(0x00000002);
SDIO_WriteData(0x00000003);
SDIO_WriteData(0x00000004);
/* RESULT */
/* reading the memory from 0x40018080 to 0x400180FC (FIFO address) everything is at 0, nothing is written */
/* other “FIFO� configuration with DPSM enabled */
SDIO_DataInitStructure.SDIO_DPSM = SDIO_DPSM_Enable;
SDIO_DataConfig(&SDIO_DataInitStructure);
/* try to write data in the FIFO */
SDIO_WriteData(0x00000005);
/* RESULT */
/* reading the memory from 0x40018080 to 0x400180FC (FIFO address). The full FIFO is written with 0x00000005 */
/* try to write again in the FIFO */
SDIO_WriteData(0x00000006);
/* RESULT */
/* reading the memory from 0x40018080 to 0x400180FC (FIFO address). The full FIFO is STILL written with 0x00000005 */
/* reinit DPSM */
SDIO_DataInitStructure.SDIO_DPSM = SDIO_DPSM_Enable;
SDIO_DataConfig(&SDIO_DataInitStructure);
/* try to write data in the FIFO */
SDIO_WriteData(0x00000007);
/* RESULT */
/* reading the memory from 0x40018080 to 0x400180FC (FIFO address). The full FIFO is written with 0x00000007 */
/* try now to access the FIFO with pointer at different address */
UI32 *ptFifo;
ptFifo = (UI32)0x40018084;
/* reinit DPSM */
SDIO_DataInitStructure.SDIO_DPSM = SDIO_DPSM_Enable;
SDIO_DataConfig(&SDIO_DataInitStructure);
/* try to write data in the FIFO */
*ptFifo = 0x00000008;
/* RESULT */
/* reading the memory from 0x40018080 to 0x400180FC (FIFO address). The full FIFO is written with 0x00000008 */
INFO: seeing the behaviour of the FIFO, I didn’t check any registers such as SDIO FIFO Counter. Because DPSM is enabled, as soon as I write to the FIFO, data are transferred.
Thanks in advance.
