PIC16C54-XT/P Microchip Technology, PIC16C54-XT/P Datasheet - Page 41

• Manufacturer Part Number: PIC16C54-XT/P
• Description: IC MCU OTP 512X12 18DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Cr

Specifications of PIC16C54-XT/P

• Core Size: 8-Bit
• Program Memory Size: 768B (512 x 12)
• Core Processor: PIC
• Speed: 4MHz
• Peripherals: POR, WDT
• Number Of I /o: 12
• Program Memory Type: OTP
• Ram Size: 25 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 6.25 V
• Oscillator Type: External
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 18-DIP (0.300", 7.62mm)
• Controller Family/series: PIC16C
• No. Of I/o's: 12
• Ram Memory Size: 25Byte
• Cpu Speed: 4MHz
• No. Of Timers: 1
• Package: 18PDIP
• Device Core: PIC
• Family Name: PIC16
• Maximum Speed: 4 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 12
• Number Of Timers: 1
• Core: PIC
• Processor Series: PIC16C
• Maximum Clock Frequency: 40 MHz
• Data Ram Size: 25 B
• Data Rom Size: 512 B
• Mounting Style: Through Hole
• Height: 3.3 mm
• Length: 22.86 mm
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Supply Voltage (max): 6.25 V
• Supply Voltage (min): 3 V
• Width: 6.35 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Connectivity: -
• Lead Free Status / Rohs Status: Details

7.7
The TO and PD 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, or a MCLR or WDT wake-up reset.
TABLE 7-6:
These STATUS bits are only affected by events listed
in Table 7-7.
TABLE 7-7:
Table 7-3 lists the reset conditions for the special
function registers, while Table 7-4 lists the reset
conditions for all the registers.
Legend: u = unchanged
Note 1: The TO and PD bits maintain their status (u) until
Power-up
WDT Time-out
SLEEP instruction
CLRWDT instruction
Legend: u = unchanged
TO
1998 Microchip Technology Inc.
1
u
1
0
0
Note:
Event
Time-Out Sequence and Power Down
Status Bits (TO/PD)
PD
does not change the TO and PD status bits.
a reset occurs. A low-pulse on the MCLR input
1
u
0
1
0
A WDT time-out will occur regardless of
the status of the TO bit. A SLEEP instruc-
tion will be executed, regardless of the sta-
tus of the PD bit.
Power-up (POR)
MCLR reset (normal operation)
MCLR wake-up reset (from SLEEP)
WDT reset (normal operation)
WDT wake-up reset (from SLEEP)
TO/PD STATUS AFTER
RESET
EVENTS AFFECTING TO/PD
STATUS BITS
RESET was caused by
TO
1
0
1
1
PD
1
u
0
1
No effect on PD
Remarks
(1)
Preliminary
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 PIC16C5X devices when a brown-out occurs,
external brown-out protection circuits may be built, as
shown in Figure 7-14 and Figure 7-15.
FIGURE 7-14: BROWN-OUT PROTECTION
FIGURE 7-15: BROWN-OUT PROTECTION
This circuit will activate reset when V
0.7V (where Vz = Zener voltage).
This brown-out circuit is less expensive, although
less accurate. Transistor Q1 turns off when V
is below a certain level such that:
33k
V
Reset on Brown-Out
DD
R1
R2
V
DD
V
10k
DD
CIRCUIT 1
CIRCUIT 2
•
R1 + R2
Q1
40k
R1
PIC16C5X
Q1
40k
MCLR
PIC16C5X
V
DD
DD
= 0.7V
MCLR
PIC16C5X
V
DS30453B-page 41
DD
goes below Vz +
DD
DD
)