Host Bus Mode
1208
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
External Peripheral Interface (EPI)
Table 17-7. EPI Host-Bus 16 Signal Connections
(1) (2)
(continued)
EPI Signal
{CSCFGEXT,CSCF
G}
BSEL
HB16 Signal
(MODE=ADMUX)
(3)
HB16 Signal
(MODE-
ADNOMUX)
B16 Signal
MODE=XFIFO)
EPI0S36
0x0-0x4
X
-
-
-
0x5
X
-
A11
0x6
X
-
-
0x7
X
-
A11
EPI0S37
0x0-0x4
X
-
-
0x5
X
-
A12
0x6
X
-
-
0x7
X
-
A12
EPI0S38
0x0-0x4
X
-
-
0x5
X
-
A13
0x6
X
-
-
0x7
X
-
A13
EPI0S39
0x0-0x4
X
-
-
0x5
X
-
A14
0x6
X
-
-
0x7
X
-
A14
EPI0S40
0x0-0x4
X
-
-
0x5
X
-
A15
0x6
X
-
-
0x7
X
-
A15
EPI0S41
0x0-0x4
X
-
-
0x5
X
-
A16
0x6
X
-
-
0x7
X
-
A16
The RDYEN in the EPIHBnCFG enables the monitoring of the external iRDY pin to stall synchronous
accesses. On the rising edge of EPI clock, if iRDY is low, access is stalled. The IRDYDLY can program
the number of EPI clock cycles in advance to the stall (1,2, or 3) as shown in
. This is a
conceptual timing diagram of how the iRDY signal works with different IRDYDLY configurations. When
enabled, the iRDY stalls the EPI's internal states, while IRDYDLY controls the delay pipeline when this
stall takes affect. The iRDY signal can be connected to multiple devices with a pull up resistor as shown in
shows how to connect the EPI signals to a16-bit SRAM and a 16-bit Flash memory with
muxed address and memory using byte selects and dual chip selects with ALE. This schematic is just an
example of how to connect the signals; timing and loading have not been analyzed. In addition, not all
bypass capacitors are shown.