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Registers
1557
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Universal Parallel Port (uPP)
32.3.3 uPP Digital Loopback Register (UPDLB)
The uPP digital loopback register (UPDLB) enables or disables the use of internal digital loopback in the
uPP peripheral. Internal loopback may be used to transfer data from one uPP interface channel to another
when the peripheral is configured in duplex mode. The interface Channel A and Channel B pins do not
need to be connected for this operation, but the proper pin multiplexing must still be applied. The UPDLB
is shown in
and described in
Figure 32-18. uPP Digital Loopback Register (UPDLB)
31
16
Reserved
R-0
15
14
13
12
11
0
Reserved
BA
AB
Reserved
R-0
R/W-0
R/W-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 32-13. uPP Digital Loopback Register (UPDLB) Field Descriptions
Bit
Field
Value
Description
31-14
Reserved
0
Reserved
13
BA
B-to-A digital loopback control. Assert to enable digital loopback, transmitting from Channel B to
Channel A.
0
Disable B-to-A digital loopback. Allows AB to be asserted.
1
Enable B-to-A digital loopback. Requires AB = 0 and the MODE bit in the uPP channel control register
(UPCTL) to be set to 2h.
12
AB
A-to-B digital loopback control. Set to enable digital loopback, transmitting from Channel A to Channel
B.
0
Disable A-to-B digital loopback. Allows BA to be asserted.
1
Enable A-to-B digital loopback. Requires BA = 0 and the MODE bit in the uPP channel control register
(UPCTL) to be set to 3h.
11-0
Reserved
0
Reserved