(
)
1
E C P D I V
N
V C L K o r O S C I
E C L K
+
=
System and Peripheral Control Registers
196
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
Architecture
2.5.1.43 ECP Control Register (ECPCNTL)
The ECP register, shown in
and described in
, configures the ECLK pin in
functional mode.
NOTE:
ECLK Functional mode configuration.
The ECLK pin must be placed into Functional mode by setting the ECPCLKFUN bit to 1 in
the SYSPC1 register before a clock source will be visible on the ECLK pin.
Figure 2-50. ECP Control Register (ECPCNTL) (offset = D4h)
31
25
24
23
22
18
17
16
Reserved
ECPSSEL
ECPCOS
Reserved
Reserved
R-0
R/W-0
R/W-0
R-0
R/W-0
15
0
ECPDIV
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 2-62. ECP Control Register (ECPCNTL) Field Descriptions
Bit
Field
Value
Description
31-25
Reserved
0
Reads return 0. Writes have no effect.
24
ECPSSEL
This bit allows the selection between VCLK and OSCIN as the clock source for ECLK.
Note: Other ECLK clock sources are available for debug purposes by configuring the
CLKTEST register.
0
VCLK is selected as the ECP clock source.
1
OSCIN is selected as the ECP clock source.
23
ECPCOS
ECP continue on suspend.
Note: Suspend mode is entered while performing certain JTAG debugging operations.
0
ECLK output is disabled in suspend mode. ECLK output will be shut off and will not be seen on
the I/O pin of the device.
1
ECLK output is not disabled in suspend mode. ECLK output will not be shut off and will be seen
on the I/O pin of the device.
22-18
Reserved
0
Reads return 0. Writes have no effect.
17-16
Reserved
0
Reads return 0 or 1 depends on what is written. The functionality of this bit is unavailable in this
device.
15-0
ECPDIV
0-FFFFh
ECP divider value. The value of ECPDIV bits determine the external clock (ECP clock) frequency
as a ratio of VBUS clock or OSCIN as shown in the formula: