AT89C5132
16.6.3.5
Busy Status
As shown in Figure 16-4 the card uses a busy token during a block write operation. This busy
status is reported by the CBUSY flag in MMSTA register and by the MCBI flag in MMINT which
is set every time CBUSY toggles, i.e. when the card enters and exits its busy state. This flag
may generate an MMC interrupt request as detailed in Section "Interrupt", page 96.
Figure 16-16. Data Stream Transmission Flows
Data Stream
Transmission
Data Stream
Initialization
Data Stream
Transmission ISR
FIFOs Filling
Write 16 Data to MMDAT
FIFOs Filling
Write 16 Data to MMDAT
FIFO Empty?
F1EI or F2EI = 1?
Start Transmission
DATEN = 1
DATEN = 0
Unmask FIFOs Empty
F1EM = 0
F2EM = 0
FIFO Filling
Write 8 Data to MMDAT
Start Transmission
DATEN = 1
DATEN = 0
FIFO Empty?
F1EI or F2EI = 1?
No More Data
To Send?
FIFO Filling
Write 8 Data to MMDAT
Mask FIFOs Empty
F1EM = 1
F2EM = 1
No More Data
to Send?
Send
STOP Command
Send
STOP Command
b. Interrupt Mode
a. Polling Mode
93
4173E–USB–09/07
ATMEL [ ATMEL ]
