
EPI Registers
1158
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
External Peripheral Interface (EPI)
16.5.18 EPIWFIFOCNT Register (Offset = 0x204) [reset = 0x4]
EPI Write FIFO Count (EPIWFIFOCNT)
This register contains the number of slots currently available in the WFIFO. This register may be used for
polled writes to avoid stalling and for blocking reads to avoid excess stalling (due to undrained writes). An
example use for writes may be:
for (idx = 0; idx < cnt; idx++) { while (EPIWFIFOCNT == 0) ; *ext_ram = *+; }
The above code ensures that writes to the address mapped location do not occur unless the WFIFO has
room. Although polling makes the code wait (spinning in the loop), it does not prevent interrupts being
serviced due to bus stalling.
EPIWFIFOCNT is shown in
and described in
.
Return to
Figure 16-47. EPIWFIFOCNT Register
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RESERVED
R-0x0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESERVED
WTAV
R-0x0
R-0x4
Table 16-31. EPIWFIFOCNT Register Field Descriptions
Bit
Field
Type
Reset
Description
31-3
RESERVED
R
0x0
2-0
WTAV
R
0x4
Available Write Transactions. The number of write transactions
available in the WFIFO.
When clear, a write is stalled waiting for a slot to become free (from
a preceding write completing).