Хост-контроллер SD / MMC (SMHC): список регистров

  DMA_REQ

DMA Request
DMA request signal state

  Unused

  FIFO_LEVEL

FIFO Level
Number of filled locations in FIFO

  RESP_IDX

Response Index
Index of previous response, including any auto-stop sent by controller

  FSM_BUSY

Data FSM Busy
Data transmit or receive state-machine is busy

  CARD_BUSY

Card Data Busy
Inverted version of DATA[0]
0: card data not busy
1: card data busy

  CARD_PRESENT

Data[3] Status
Level of DATA[3], checks whether card is present
0: card not present
1: card present

  FSM_STA

Command FSM States
0000: Idle
0001: Send init sequence
0010: TX CMD start bit
0011: TX CMD TX bit
0100: TX CMD index + argument
0101: TX CMD CRC7
0110: TX CMD end bit
0111: RX response start bit
1000: RX response IRQ response
1001: RX response TX bit
1010: RX response CMD index
1011: RX response data
1100: RX response CRC7
1101: RX response end bit
1110: CMD path wait NCC
1111: Wait; CMD-to-response turnaround

  FIFO_FULL

FIFO Full
1: FIFO full
0: FIFO not full

  FIFO_EMPTY

FIFO Empty
1: FIFO Empty
0: FIFO not Empty

  FIFO_TX_LEVEL

FIFO TX Water Level Flag
0: FIFO didn't reach transmit trigger level
1: FIFO reached transmit trigger level

  FIFO_RX_LEVEL

FIFO RX Water Level Flag
0: FIFO didn't reach receive trigger level
1: FIFO reached receive trigger level

Команда U-Boot для чтения регистра

Bit fields structure

typedef union  smhc_status
{
  struct
  {
   unsigned fifo_rx_level : 1;
   unsigned fifo_tx_level : 1;
   unsigned fifo_empty : 1;
   unsigned fifo_full : 1;
   unsigned fsm_sta : 4;
   unsigned card_present : 1;
   unsigned card_busy : 1;
   unsigned fsm_busy : 1;
   unsigned resp_idx : 6;
   unsigned fifo_level : 9;
   unsigned unused0 : 5;
   unsigned dma_req : 1;
  } b;
   unsigned long w;
} SMHC_STATUS