PIC16LF18854 Datasheet, PDF (101/668 Pages) Microchip Technology – C Compiler Optimized RISC Architecture

PIC16(L)F18856/76
5.1 Power-On Reset (POR)
The POR circuit holds the device in Reset until VDD has
reached an acceptable level for minimum operation.
Slow rising VDD, fast operating speeds or analog
performance may require greater than minimum VDD.
The PWRT, BOR or MCLR features can be used to
extend the start-up period until all device operation
conditions have been met.
5.2 Brown-Out Reset (BOR)
The BOR circuit holds the device in Reset when VDD
reaches a selectable minimum level. Between the
POR and BOR, complete voltage range coverage for
execution protection can be implemented.
The Brown-out Reset module has four operating
modes controlled by the BOREN<1:0> bits in
Configuration Words. The four operating modes are:
• BOR is always on
• BOR is off when in Sleep
• BOR is controlled by software
• BOR is always off
Refer to Table 5-1 for more information.
The Brown-out Reset voltage level is selectable by
configuring the BORV bit in Configuration Words.
A VDD noise rejection filter prevents the BOR from
triggering on small events. If VDD falls below VBOR for
a duration greater than parameter TBORDC, the device
will reset. See Figure 5-2 for more information.
TABLE 5-1: BOR OPERATING MODES
BOREN<1:0>
SBOREN
Device Mode
BOR Mode
Instruction Execution upon:
Release of POR or Wake-up from Sleep
11
X
X
Active
Wait for release of BOR⁽¹⁾ (BORRDY = 1)
Awake
Active
Waits for release of BOR (BORRDY = 1)
10
X
Sleep
Disabled ^{Waits for BOR Reset release}
1
01
0
00
X
X
Active
Waits for BOR Reset release (BORRDY = 1)
X
Disabled
Begins immediately (BORRDY = x)
X
Disabled
Note 1: In these specific cases, “Release of POR” and “Wake-up from Sleep”, there is no delay in start-up. The BOR
ready flag, (BORRDY = 1), will be set before the CPU is ready to execute instructions because the BOR
circuit is forced on by the BOREN<1:0> bits.
5.2.1 BOR IS ALWAYS ON
When the BOREN bits of Configuration Words are
programmed to ‘11’, the BOR is always on. The device
start-up will be delayed until the BOR is ready and VDD
is higher than the BOR threshold.
BOR protection is active during Sleep. The BOR does
not delay wake-up from Sleep.
5.2.2 BOR IS OFF IN SLEEP
When the BOREN bits of Configuration Words are
programmed to ‘10’, the BOR is on, except in Sleep.
The device start-up will be delayed until the BOR is
ready and VDD is higher than the BOR threshold.
BOR protection is not active during Sleep. The device
wake-up will be delayed until the BOR is ready.
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Preliminary
DS40001824A-page 101