ST40RA
5 System configuration
ST40RA EMI pin
Peripheral
SFlash
SDRAM
MPX
MPX/EMPI
MPX bus
NOTMACK
(Master)
EMI_BUS_GRANT EMI_BUS_GRANT EMI_BUS_GRANT MPX bus
acknowledge
acknowledge
FCLKOUT
NOTFBAA
-
-
FLASHCLOCK
Unconnected/
-
-
-
-
-
-
b
connected
NOTESCS0
NOTESCS1
NOTESCS2
-
-
-
-
-
-
-
-
-
-
-
-
MBXINT
EMPIDREQ0
EMPIDRAK0
Table 8: EMI pin functions
a. When the EMI is configured in master mode (MODE9 = H), and an external slave DMA asks for
access to the bus (using NOTMACK or NOTMREQ), RFSH_PENDING and ACC_PENDING are
used to signal that, while the external DMA request has been granted and the DMA is using the bus,
a refresh time out occurred, or that the EMI has been asked for a new access. A bus arbiter, if
present, can use this information to give back the bus to the EMI to allow a refresh operation, or
improve bandwidth. When the EMI is in slave mode (MODE9 = L), RFSH_PENDING is always
deasserted (so EPENDING = ACC_PENDING), and the pin is used to signal to the external bus
arbiter that the EMI needs to use the bus.
b. NOTFBAA is an output of the ST40RA, and an input to the memory device. The pin must be left
unconnected from the ST40RA side and tied low at the memory device side if the memory is an Intel
or an STM part. It needs to be connected if the SFlash is an AMD.
ADCS 7260755H
STMicroelectronics
20/94
STMICROELECTRONICS [ ST ]
