Figure 1-106. External Interrupt n Counter (XINTnCTR) (Address 7078h)
15
0
INTCTR[15-8]
R-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 1-131. External Interrupt n Counter (XINTnCTR) Field Descriptions
Bits
Field
Description
15-0
INTCTR
This is a 16-bit free-running up-counter that is clocked at the SYSCLKOUT rate. The counter value
is reset to 0x0000 when a valid interrupt edge is detected and then continues counting until the next
valid interrupt edge is detected. When the interrupt is disabled, the counter stops. The counter is a
free-running counter and wraps around to zero when the maximum value is reached. The counter is a
read only register and can only be reset to zero by a valid interrupt edge or by reset.
1.7 VREG/BOR/POR
Although the core and I/O circuitry operate on two different voltages, these devices have an on-chip voltage
regulator (VREG) to generate the V
DD
voltage from the V
DDIO
supply. This eliminates the cost and area of a
second external regulator on an application board. Additionally, internal power-on reset (POR) and brown-out
reset (BOR) circuits monitor both the V
DD
and V
DDIO
rails during power-up and run mode, eliminating a need for
any external voltage supervisory circuits.
The V
DD
BOR is only valid when the VREG is enabled. If VREG is disabled, and external LDO is used for 1.8V,
then there is no BOR functIon on V
DD
.
1.7.1 On-chip Voltage Regulator (VREG)
An on-chip voltage regulator facilitates the powering of the device without adding the cost or board space of a
second external regulator. This linear regulator generates the core V
DD
voltage from the V
DDIO
supply. Therefore,
although capacitors are required on each V
DD
pin to stabilize the generated voltage, power need not be supplied
to these pins to operate the device. Conversely, the VREG can be bypassed or overdriven, should power or
redundancy be the primary concern of the application.
1.7.1.1 Using the on-chip VREG
To utilize the on-chip VREG, the VREGENZ pin should be pulled low and the appropriate recommended
operating voltage should be supplied to the V
DDIO
and V
DDA
pins. In this case, the V
DD
voltage needed by
the core logic will be generated by the VREG. Each V
DD
pin requires on the order of 1.2 μF capacitance for
proper regulation of the VREG. These capacitors should be located as close as possible to the device pins.
Refer to the device datasheet for the acceptable range of capacitance.
1.7.1.2 Bypassing the on-chip VREG
To conserve power, it is also possible to bypass the on-chip VREG and supply the core logic voltage to the V
DD
pins with a more efficient external regulator. To enable this option, the VREGENZ pin must be pulled high. Refer
to the device datasheet for the acceptable range of voltage that must be supplied to the V
DD
pins.
System Control and Interrupts
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
193
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
Страница 2: ......