PIC16C505-04I/P Microchip Technology Inc., PIC16C505-04I/P Datasheet - Page 36

• Manufacturer Part Number: PIC16C505-04I/P
• Description: 14 PIN, 1.5 KB OTP, 72 RAM, 12 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16C505-04I/P

• Cpu Speed: 5 MIPS
• Eeprom Memory: 0 Bytes
• Input Output: 11
• Memory Type: OTP
• Number Of Bits: 8
• Package Type: 14-pin PDIP
• Programmable Memory: 1.5K Bytes
• Ram Size: 72 Bytes
• Speed: 4 MHz
• Timers: 1- 8-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC16C505
7.7
The TO, PD, and RBWUF bits in the STATUS register
can be tested to determine if a RESET condition has
been caused by a power-up condition, a MCLR or
Watchdog Timer (WDT) reset.
TABLE 7-7:
7.8
A brown-out is a condition where device power (V
dips below its minimum value, but not to zero, and then
recovers. The device should be reset in the event of a
brown-out.
To reset PIC16C505 devices when a brown-out
occurs, external brown-out protection circuits may be
built, as shown in Figure 7-12 and Figure 7-13.
FIGURE 7-12: BROWN-OUT PROTECTION
DS40192C-page 36
RBWUF TO
Legend: u = unchanged
Note 1: The TO, PD, and RBWUF bits maintain their
This circuit will activate reset when V
Vz + 0.7V (where Vz = Zener voltage).
Note 1: Pin must be confirmed as MCLR.
0
0
0
0
0
1
33k
V
Time-Out Sequence, Power Down,
and Wake-up from SLEEP Status Bits
(TO/PD/RBWUF)
Reset on Brown-Out
status (u) until a reset occurs. A low-pulse on the
MCLR input does not change the TO, PD, and
RBWUF status bits.
DD
0
0
1
1
u
1
10k
PD
TO/PD/RBWUF STATUS
AFTER RESET
CIRCUIT 1
0
u
0
1
u
0
WDT wake-up from
SLEEP
WDT time-out (not from
SLEEP)
MCLR wake-up from
SLEEP
Power-up
MCLR not during SLEEP
Wake-up from SLEEP on
pin change
Q1
40k*
MCLR
V
RESET caused by
DD
(1)
DD
PIC16C505
goes below
DD
)
FIGURE 7-13: BROWN-OUT PROTECTION
FIGURE 7-14: BROWN-OUT PROTECTION
This brown-out circuit is less expensive, although
less accurate. Transistor Q1 turns off when V
is below a certain level such that:
Note 1: Pin must be confirmed as MCLR.
This brown-out protection circuit employs Microchip
Technology’s
There
accommodate 5V to 3V systems.
V
SS
MCP809
RST
are
R1
R2
V
DD
V
7
V
V
DD
MCP809
DD
DD
CIRCUIT 2
CIRCUIT 3
different
capacitor
•
bypass
R1 + R2
1999 Microchip Technology Inc.
R1
microcontroller
trip
Q1
40k*
V
DD
MCLR
point
= 0.7V
V
PIC12C5XX
DD
(1)
selections
PIC16C505
MCLR
supervisor.
DD
to