LM3S1G21 Datasheet, PDF (468/955 Pages) Texas Instruments – Stellaris® LM3S1G21 Microcontroller

External Peripheral Interface (EPI)
Table 10-4. Capabilities of Host Bus 8 and Host Bus 16 Modes (continued)
Host Bus Type MODE
CSCFG
Max # of
External
Devices
BSEL
Byte Access
Available
Address
Addressable
Memory
HB8
0x1
0x0, 0x1
1
N/A
Always
20 bits
1 MB
HB8
0x1
0x2
2
N/A
Always
19 bits
512 kB
HB8
0x1
0x3
2
N/A
Always
18 bits
256 kB
HB8
0x3
0x1
1
N/A
Always
none
-
HB8
HB16
HB16
HB16
HB16
HB16
HB16
HB16
HB16
HB16
HB16
HB16
HB16
0x3
0x3
2
N/A
Always
0x0
0x0, 0x1
1
0
No
0x0
0x0, 0x1
1
1
Yes
0x0
0x2
2
0
No
0x0
0x2
2
1
Yes
0x0
0x3
2
0
No
0x0
0x3
2
1
Yes
0x1
0x0, 0x1
1
0
No
0x1
0x0, 0x1
1
1
Yes
0x1
0x2
2
0
No
0x1
0x2
2
1
Yes
0x1
0x3
2
0
No
0x1
0x3
2
1
Yes
none
28 bits^a
26 bits^b
27 bits^a
25 bits^b
26 bites^a
24 bits^b
12 bits^a
10 bits^b
11 bits^a
9 bits^b
10 bits^a
8 bits^b
-
512 MB
128 MB
256 MB
64 MB
128 MB
32 MB
8 kB
2 kB
4 kB
1 kB
2 kB
512 B
HB16
0x3
0x1
1
0
No
none
-
HB16
0x3
0x1
1
1
Yes
none
-
HB16
0x3
0x3
2
0
No
none
-
HB16
0x3
0x3
2
1
Yes
none
-
a. If byte selects are not used, data accesses are on 2-byte boundaries. As a result, the available address space is doubled.
b. Two EPI signals are used for byte selects, reducing the available address space by two bits.
Table 10-5 on page 468 shows how the EPI[31:0] signals function while in Host-Bus 8 mode.
Notice that the signal configuration changes based on the address/data mode selected by the MODE
field in the EPIHB8CFG2 register and on the chip select configuration selected by the CSCFG field
in the same register.
Although the EPI0S31 signal can be configured for the EPI clock signal in Host-Bus mode, it is not
required and should be configured as a GPIO to reduce EMI in the system. Any unused EPI controller
signals can be used as GPIOs or another alternate function.
Table 10-5. EPI Host-Bus 8 Signal Connections
EPI Signal
CSCFG
HB8 Signal (MODE
=ADMUX)
EPI0S0
EPI0S1
EPI0S2
EPI0S3
EPI0S4
EPI0S5
X^a
AD0
X
AD1
X
AD2
X
AD3
X
AD4
X
AD5
HB8 Signal (MODE
=ADNOMUX (Cont.
Read))
D0
D1
D2
D3
D4
D5
HB8 Signal (MODE
=XFIFO)
D0
D1
D2
D3
D4
D5
468
January 22, 2012
Texas Instruments-Production Data