PIC16C63A/65B/73B/74B
FIGURE 13-7:
WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4
Q1
Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4
Q1 Q2 Q3 Q4
Q1 Q2 Q3
Q4
Q1 Q2 Q3 Q4
OSC1
CLKOUT
(4)
INT pin
INTF Flag
(INTCON<1>)
GIE bit
(INTCON<7>)
INSTRUCTION FLOW
PC
Instruction
Fetched
Instruction
Executed
PC
Inst(PC) = SLEEP
Inst(PC - 1)
PC+1
Inst(PC + 1)
SLEEP
PC+2
PC+2
Inst(PC + 2)
Inst(PC + 1)
Dummy cycle
PC + 2
0004h
Inst(0004h)
Dummy cycle
0005h
Inst(0005h)
Inst(0004h)
Processor in
SLEEP
Interrupt Latency
(2)
T
OST
(2)
Note
1:
2:
3:
4:
XT, HS or LP oscillator mode assumed.
T
OST
= 1024Tosc (drawing not to scale). This delay is not present in RC osc mode.
GIE = ’1’ assumed. After wake- up, the processor jumps to the interrupt routine. If GIE = ’0’, execution will continue in-line.
CLKOUT is not available in these osc modes, but shown here for timing reference.
13.9
Program Verification/Code
Protection
If the code protection bit(s) have not been pro-
grammed, the on-chip program memory can be read
out for verification purposes.
Note:
Microchip does not recommend code pro-
tecting windowed devices. Devices that
are code protected may be erased, but not
programmed again.
The device is placed into a Program/Verify mode by
holding the RB6 and RB7 pins low, while raising the
MCLR (V
PP
) pin from V
IL
to V
IHH
(see programming
specification). RB6 becomes the programming clock
and RB7 becomes the programming data. Both RB6
and RB7 are Schmitt Trigger inputs in this mode.
After RESET, to place the device into Programming/
Verify mode, the program counter (PC) is at location
00h. A 6-bit command is then supplied to the device.
Depending on the command, 14 bits of program data are
then supplied to or from the device, depending if the
command was a load or a read. For complete details of
serial programming, please refer to the PIC16C6X/7X
Programming Specifications (Literature #DS30228).
13.10 ID Locations
Four memory locations (2000h - 2003h) are designated
as ID locations where the user can store checksum or
other code identification numbers. These locations are
not accessible during normal execution, but are read-
able and writable during program/verify. It is recom-
mended that only the four least significant bits of the ID
location are used.
FIGURE 13-8:
TYPICAL IN-CIRCUIT
SERIAL PROGRAMMING
CONNECTION
To Normal
Connections
PIC16CXX
V
DD
V
SS
MCLR/V
PP
RB6
RB7
13.11
In-Circuit Serial Programming
PIC16CXX microcontrollers can be serially pro-
grammed while in the end application circuit. This is
simply done with two lines for clock and data, and three
other lines for power, ground and the programming
voltage. This allows customers to manufacture boards
with unprogrammed devices, and then program the
microcontroller just before shipping the product. This
also allows the most recent firmware or a custom firm-
ware to be programmed.
External
Connector
Signals
+5V
0V
V
PP
CLK
Data I/O
V
DD
To Normal
Connections
DS30605C-page 98
2000 Microchip Technology Inc.
MICROCHIP [ MICROCHIP TECHNOLOGY ]
