Rainbow Electronics AT89C51SND1C - Manual (Page 124)

124
AT8xC51SND1C
4109E–8051–06/03
Interrupt
Description As shown in Figure 89, the MMC controller implements eight interrupt sources reported
in MCBI, EORI, EOCI, EOFI, F2FI, F1FI, and F2EI flags in MMCINT register. These
flags are detailed in the previous sections.
All these sources are maskable separately using MCBM, EORM, EOCM, EOFM, F2FM,
F1FM, and F2EM mask bits respectively in MMMSK register.
The interrupt request is generated each time an unmasked flag is set, and the global
MMC controller interrupt enable bit is set (EMMC in IEN1 register).
Reading the MMINT register automatically clears the interrupt flags (acknowledgment).
This implies that register content must be saved and tested interrupt flag by interrupt
flag to be sure not to forget any interrupts.
Figure 89. MMC Controller Interrupt System
MMC Interface
Interrupt Request
MCBI
MMINT.7
EOCM
MMMSK.5
EMMC
IEN1.0
MCBM
MMMSK.7
EORM
MMMSK.6
EOFI
MMINT.4
F2FM
MMMSK.3
EOFM
MMMSK.4
EORI
MMINT.6
F2FI
MMINT.3
EOCI
MMINT.5
F2EM
MMMSK.1
F1FM
MMMSK.2
F1EI
MMINT.0
F1EM
MMMSK.0
F1FI
MMINT.2
F2EI
MMINT.1