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2014-07-02 - Gecko Family - d0001_Rev1.30
138
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the LSB of the address driven into the EBI_AD bus, i.e. the EBI_AD[0]-bit, corresponds to
the second least significant bit of the address, i.e. ADDR[1]. At the external device, the LSB
of the address must be tied either low or high in order to create a full address.
Figure 14.3. EBI Address Latch Setup
EBI
(EFM32)
Ex t ernal
Async.
Device
Lat ch
EBI_AD
ADDR
DATA
Cont rol
ALE
At the start of the transaction the address is output on the EBI_AD lines. The Latch is controlled by the
ALE (Address Latch Enable) signal and stores the address. Then the data is read or written according
to operation. Read and write signals are shown in Figure 14.4 (p. 138) and Figure 14.5 (p. 138)
respectively.
Figure 14.4. EBI Multiplexed 16-bit Data, 16-bit Address Read Operation
ADDR[16:1]
EBI_AD[15:0]
EBI_ALE
ADDRSETUP
(1, 2, 3, ...)
Z
DATA[15:0]
EBI_CSn
EBI_REn
Z
RDSETUP
(0, 1, 2, ...)
RDSTRB
(1, 2, 3, ...)
RDHOLD
(0, 1, 2, ...)
Figure 14.5. EBI Multiplexed 16-bit Data, 16-bit Address Write Operation
ADDR[16:1]
EBI_AD[15:0]
EBI_ALE
ADDRSETUP
(1, 2, 3, ...)
DATA[15:0]
EBI_CSn
EBI_WEn
Z
WRSETUP
(0, 1, 2, ...)
WRSTRB
(1, 2, 3, ...)
WRHOLD
(0, 1, 2, ...)
ADDRHOLD
(0, 1, 2, ...)
This mode allows 24-bit address with 8-bit data multiplexed on the EBI_AD lines. The upper 8 bits of
the EBI_AD lines are consecutively used for the highest 8 bits and the lowest 8 bits of the address. The
lower 8 bits of the EBI_AD lines are used for the middle 8 address bits and for data. This mode is set
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